atomic structure - Science-Education-Research

Teenage lust and star-crossed electrons

A new study reports a creative approach to modelling the atom motivated by a love story

Keith S. Taber

Perhaps it would be better not to introduce an orbital model until we feel learners are ready to appreciate the quantum jump from concentric orbits to fuzzy, overlapping, infinitely-extended patterns of electronic probability, and the associated complex patterns of energy levels they generate.

A scene from the play 'Romeo and Juliet' — "Grade: B-.
Comment: Your model of the heteronuclear molecule of Romeo-Juliet was creative and aesthetically pleasing, but it was inconsistent because you used rope to stand for the covalent bond when you are representing electrons with apples." (Image by Николай Оберемченко from Pixabay)

The science curriculum contains a good deal of abstract material that is both challenging, and – sadly – not always found intrinsically interesting, to many learners. The teacher has to find what can 'make the unfamiliar familiar', something I have written quite a lot about on this site.

Read about teaching as making the unfamiliar familiar

Modelling 'the' atom

One such abstract topic is the structure of 'the' atom ¹ – an area where learners will likely come across multiple models and diverse representations, and where what is being modelled and represented (as a quanticle – a quantum object) simply cannot be adequately represented concretely. Given that, it is hardly surprising that often even keen and capable learners show alternative conceptions in this topic (Taber, 2002 [Download paper]).

I was therefore intrigued by a recent research paper that described an approach to progressing learners' ideas about atomic structure by asking them to engage with a story. Narrative is a recognised way of helping make the unfamiliar familiar, and here a story was referenced that is familiar to many people: that of Shakespeare's 'star-crossed lovers': Romeo and Juliet.

So, in the storyline, electrons were named after characters from the tragic tale. It is common to relate abstract chemical ideas to social relations (chemistry uses such metaphors as 'sharing electrons', 'nucleus loving' species, reagent species that 'attack' other molecules, and substances that 'compete') – but this does risk the anthropomorphism (that is, treating non-human entities as if they have human qualities) actually confusing learners.

Read about anthropomorphism and science

That is, molecules and ions, and nuclei and electrons are not like people, and do not think or have desires, and so they do not act from motivations such as love or hate or jealousy…

Perhaps this seems SO OBVIOUS that only the weakest student could possibly get confused and think otherwise?

But I know from my own research (e.g., Taber & Watts, 1996 [download paper]) that actually even studious, intelligent learners can come to habitually use anthropomorphic language without noticing that they are explaining chemistry in terms that would only make sense if atoms and molecules and ions and electrons did have preferences, and could think for themselves, and did act accordingly!

Atoms can not care about anything – so they do not care about how many electrons they have, and they never deliberately do anything in order to obtain full shells or octets (as they cannot act under their own volition, of course). But many generally successful, hard-working, intelligent, learners in chemistry classes all over the world seem to think otherwise (Taber, 1998 [Download paper]).

Read about the octet framework – an alternative conceptual framework

Likewise, electrons do not care if they are in an atom or not, or whether they are spin-paired or not (and if so, which other, indistinguishable, electron they are paired with), or which energy level of a system they populate.

The authors of the recent paper (which is open access, so freely available for anyone who wishes to download/read it) claim that students found the story-related activity engaging (which certainly seems likely) and that it helped address some misconceptions about atomic structure. They note that:

"Students do not clearly understand the concept of an orbital" (Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024)

This is a topic that has long interested me so I took a look at the activity the researchers had devised. The learners were

"10th-grade classes, with the participants' average age being between 15 and 16, attending a technical computer science high school ¹…[who] had already studied the atomic model in their chemistry classes during the first half of the year."
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

I have taught a basic (planetary) model of atomic structure to students at this age, and also more advanced models to 16-19 year old learners (on A level courses), so I was keen to read about the activity. The authors did not include an explicit statement of the curriculum content which was being treated as target knowledge, although they did include a discussion of their rationale for the story, as well as comments on student work, from which some features could be deduced or inferred. (I would have found it useful to have read an explicit statement of just what the learners were expected to know – what the 'correct' model was meant to be – at the outset of the paper.)

I approached the paper thinking it was ambitious to teach an orbital model of the atom to students of this age. My reading of the story (reproduced below) reinforced that initial impression (I admit, I was challenged in places!) – although the authors certainly felt the students in their research coped well with the challenge.

Although I felt I struggled interpreting some features of the narrative,

A student with a specific learning disorder (SLD), mentioned, "The connection of a fairly complicated topic with such a simple story"
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

It is important to note that the teaching scheme adopted a dialogic approach, where class discussions were included at two points after the students had worked in groups on parts of the activity. The activity was also conceptualised as being part of an enquiry-based learning cycle. So, the material below should be read accordingly, as it does not reflect this wider classroom context.

Read about dialogic teaching

Read about enquiry-based science education

The story

The story is broken into four parts, each leading to a task for the learners (working in groups) to engage in.

Prologue

"Romeo is a bold and dynamic electron found in an atom with seven energy levels. He is at the 4s energy level, together with the faithful Mercutio, his companion on raids. Always upside down compared to him, but then there is no place for two equal electrons in their crew. The two are part of the Montague family, known for being particularly lively.

Juliet is an electron in 2s, she is more tied to her nucleus and in fact she is a Capulet, a rival family to that of the Montagues and decidedly more calm. Juliet is always accompanied by her nurse; they too are turned upside down with respect to each other.

There is a grand ball to which everyone is invited, and, to better organize their arrangement, there is a need to schematize their position."

[Instructions to learners: "Discuss with your classmates what should be the design of the atom where the two families «are» and build
a model"]
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

Chapter 1 – part 1

"At one point during the dance, Romeo notices Juliet in her orbital, and, even if he occasionally gets close to her, he is unable to stay there permanently: quivering with love, he asks who knows her and what her tastes are in terms of radiations (electrons are well known to be romantics). He discovers that Juliet is obsessed with color harmony and that the color she prefers is purple "486 nm". To get noticed he wants to perform his famous photon–spectroscopic serenade and jump to emit a purple trail.

[Instructions to learners: "Discuss with your teammates to help Romeo understand how far he will have to jump and whether or not he would have gotten closer to Juliet in this way."]
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

Chapter 1 – part 2

"The two are deeply in love and would like to spend the rest of their days together. But Juliet's family hinders them, crying scandal: a Montague cannot be so tied to the nucleus! What to do? The nurse offers Romeo the chance to take her place, but, for her, this would mean losing her place next to Juliet. Romeo and Juliet, very hesitant, then decide to move towards the orbitals occupied by the Montagues. But how to get up there?

While the couple is tormented by this problem, an enlightened friar, Lory, arrives to their rescue with two THz 457s, offering to give them a lift. Despite this help, Romeo and Juliet are unable to reach the Montague orbital, so they loudly invoke another friar, Enzo, asking for new help.

[Instructions to learners: Discuss with your teammates to understand how far they will jump thanks to the first photons and which photons Fra Enzo will have to carry for the two lovers to reach the Montague orbital."]
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

Chapter 2 and epilogue

"Juliet's escape has thrown the entire atomic balance into crisis, forcing some Montagues to change levels in order to maintain overall stability. Then, when the couple comes to the Montagues, they cry out for revenge, and the couple is then forced to flee again.

The Montagues set out in search of Romeo and Juliet but fail because it is not possible to reconstruct the trajectory followed by the two lovers.

The story unfortunately ends in tragedy: the two do manage to free themselves from the influence of their families, but they still understand that they cannot be together. Now condemned to separation, the two lovers decide to draw up a schema of the place (the atom) where they met to remember it forever.

[Instructions to learners: "Discuss with your teammates why this trajectory cannot be reconstructed. End the story with a tragic ending, explaining the reasons for the separation sentence.

EPILOGUE Construct with your teammates a possible model of the scheme realized by Romeo and Juliet."]
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

Interpreting the narrative

Reading the account I had a very mixed response. I am very keen on approaches that use the familiar everyday as ways into teaching complex, abstract ideas; but subject to two provisos:

these everyday analogies are interim supports ('scaffolds'), to be withdraw as soon as they are no longer needed;
teaching needs to focus on the 'negative analogy' (things that do not map across) as well as the 'positive analogy' (the aspects of the comparison that 'work').

The approach here seemed somewhat different. The learners had already been taught a model of the atom earlier in the year, and this activity was intended to be an opportunity to review this prior learning and apply it – and an opportunity for teachers to identify any alternative conceptions elicited by the activity.

Metaphorical meanings?

Romeo and Juliet are not the lovers in the stage play, but electrons. Therefore, in reading the story I identified scientific information (electron Romeo is in a 4s orbital in an atom) and material that seemed to be metaphorical (the electrons Romeo and Mercutio go on 'raids'). I therefore saw the task of reading the story as being in part a decoding of the metaphors that were used.

So, the idea of Romeo and Mercutio being relatively "upside down" was not to be taken literally (electrons do not have ups or downs) but to be a metaphor for spin +¹/₂ and spin –¹/₂, often referred to metaphorically as 'spin up' and 'spin down'. Going on raids was more tricky: in some chemical reactions electron pairs are considered to shift during bond formation (or bond breaking, but that would not refer to an atomic species), but 'raid' suggests a temporary excursion.

I could not understand in what sense Mercutio (the electron, not the fictional character) could be said to be faithful. Electrons respond to physical forces, not personal attachments. Perhaps, I was over-thinking this, and not all the narrative elements did map onto the atomic system? Perhaps that was meant to be part of the challenge for the learners?

A fundamental concern with this kind of comparison is that all electrons are inherently identical, and are only distinguished by the accidental features they acquire in a particular system.

A 2s electron is on average closer to the nucleus, and experiences a greater effective core charge (it is not shielded as much from the nucleus as a 4s electron is) – so the 'tie' (bond) to the nucleus can be understood as analogous to the attractive force operating between the electron and nucleus. ²
The reference to being more calm perhaps refers to how the 2s level is at a 'lower' energy so the 'particularly lively' 4s electrons can be more dynamic?

If Romeo and Mercutio, or even Romeo and Juliet, were swapped it could make absolutely no difference and no one could tell. By giving electrons personal identities they seem to be more like us and less like electrons. Electrons cannot be bold or calm. Romeo and Juliet behave differently because they are in different orbitals at different energy levels, not because they are different electrons. Could learners miss this critical point? If Juliet (or Romeo) moved to a different energy level then she (or he) would change 'personality' – but that would undermine the narrative.

I was not sure how the two families related to anything. Within an atom we could class some electrons alike because they are in the same 'shell' (have the same principal quantum number) – so perhaps the two families were in the n=2 and n=4 levels (the L and N shells being their metaphorical 'houses'). I also could not understand where the ball was meant to be held:

were the electrons to be moved to a new set of orbitals (requiring promotion)
were the electrons meant be moved to outside the atom (requiring ionisation), or
was the ball to take place with the electrons in their current orbitals (but for some reason behaving differently than when no dance was taking place?)

The attraction between Romeo and Juliet (the electrons, not the fictional lovers) was difficult to understand. Certainly, if we adopt a model of electrons moving about in different orbitals ³ then they could sometimes be nearer to each other as atomic orbitals interpenetrate – and if so they would influence each other more (due to their charge and spin) at these times: but this would primarily be a repulsion.

Interpenetrating fields of play. If two sports pitches were marked out overlapping on the same ground, then there would be places that were part of both fields of play.

(Consider a school with very limited space for sports pitches. Perhaps they mark up a soccer pitch and a field hockey pitch overlapping. If both soccer and hockey players train at the same time there will be places that are part of both pitches, and players from the two sports can come close together in those areas. {This is just an analogy. The two sports would need to schedule practice at different times to avoid accidents!})

It seemed to me that the learners were being asked to read the account at two levels – some features of the story were metaphors (such as when the lovers left the atom only to find they had separate indeterminate trajectories) when other features seemed to be simply plot devices to provde an engaging narrative. I thought that the students were being asked to work out which bits of the story they should take seriously as corresponding to part of an atomic model, and which just moved the narrative on. I though this might be challenging for the 14-15 year old learners (as I was struggling!)

Orbitals and transitions

Some features of the story seemed potentially likely to encourage alternative conceptions. Juliet's preference for light of wavelength 486 nm risks the association of a spectral line with an electron or an energy level, rather than with a transition.

The specific references to 486 nm and 457 THz radiation seemed to suggest that a quantative model was needed – where an atom would actually show spectral lines reflecting transitions associated with radiation of these specific characteristics.

The rationale

Unlike the students, I had access to some of the resource designers' thinking as the paper included a rationale for the storyline. This acknowledged that

The specific location of the grand ball remains implicit [?], as it is challenging to conceive of electrons dancing outside the metaphorical context of "moving swiftly". However, all the other character details are essential for initiating the story and allowing mathematical and physical problems and situations to emerge."
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

This seemed to confirm that the learners were expected to build a quantitative model. This was reiterated later in the rationale

"Through calculations of energy transitions and the resulting orbital distances, students gain insight into the quadratic proportionality that underlies these phenomena [?], prompting a gradual reshaping of their personal notions regarding orbital distances."
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

I was not sure what was mant by 'orbital distances', and return to this point below. I was also not sure how quadratic proportionality underlay energy transitions.

This was only one of the points in the paper where I got the impression that in the teaching model adopted, energy levels and orbitals were not only being associated, but at times almost seen as equivalent and interchangeable.

A diagnostic assessment opportunity

The rationale seemed to confirm that the activity was deliberately testing whether students associated spectral lines with energy levels rather than transitons between levels,

"To elucidate the intriguing connection between emission and electron transitions to different energy levels, we introduce a romantic-comedic twist, employing Juliet's passion for color harmony as a plot device. Juliet's preference for the color purple is strategically chosen to align with her energy level, prompting students to contemplate the intriguing relationship between spectroscopy lines and electron energy transitions."
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

On the other hand, my suspicion that I had been reading too much into the narrative, and trying too hard to interpret plot twists was rather undermined by being told,

"Take, for instance, Romeo's desire to gain Juliet's attention and their joint pursuit of a life away from their feuding families. This narrative intricately parallels the fundamental interplay of orbitals within the model, establishing a direct and compelling link between the characters' human drama and the pivotal role of orbitals in the model."
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

Indeed? I was struggling to map across some of the story, even when (unlike the students) I had access to the rationale:

"At the outset, the consequences of Romeo and Juliet's choices become apparent: the voids within the nucleus [?] are replenished with new electrons [?], ultimately disturbing the equilibrium of the two feuding families. This disruption leads them to share orbits [sic], not fueled by anger but by fate. The Montagues seek revenge, yet they grapple with the inability to reconstruct the electrons' orbitals due to the uncertainty principle."
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

A lot of this went over my head.

The uncertainty principle would not interfere with characterising orbitals, only with being able to posit specific electron trajectories. The orbitals do not belong to electrons ("the electrons' orbitals") but are characteristic of an atomic system with its configuration of charges.

A hybrid model?

Perhaps, in part, my confusion was due to my not being clear about what the target knowledge was- exactly which kind of model was it hoped the students would produce?

"After studying the planetary and Bohr atomic models, students cannot easily move beyond them"
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

It seemed clear from the paper that the learners were expected to have moved beyond a model with planetary orbits, to a model with orbitals, and so from the idea of electrons moving on definite trajectories, to being found somewhere within the orbitals. ³

There was historically a range of models of the atom (even 'the Bohr model' was actaully a series of models), and long ago Rosaria Justi and John Gilbert (Justi & Gilbert, 2000) pointed out that often in teaching we end up presenting 'hybrid' models – that is, models which have features drawn from across several of the different scientific models. Did the curriculum these students followed set out such a hybrid model for students to learn? ⁴

An atom with seven energy levels?

At the start of the story, the students were told "Romeo is …found in an atom with seven energy levels". I am not sure any real atom could only have seven energy levels. My understanding is that any atom has in principle an infinite number of energy levels, but the the spacing of the levels gets successively smaller, so they converge on a limit (which makes ionisation feasible). Even the hydrogen atom has an infinite number of energy levels, but only one is populated with an electron.

So, I wondered if possibly this was meant to be read as "Romeo is …found in an atom with seven populated energy levels"?

A sensible starting point for a student is to assume the atom is initially in its ground state (as under normal circumstances they usually are). If the reference to seven energy levels means populated energy levels, and students are to assume the atom starts in the ground state then presumably learners are meant to assume the atom they need to model is one of the first transition series (i.e., elements with electronic configurations from 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹ to 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰: that is an atom from one of the elements scandium to zinc).

However, later there is a reference to electron Romeo wanting to "jump to emit a purple trail". But he needs to jump 'down' (to a lower energy level) both to get closer to Juliet and indeed to "emit a purple trail" (i.e., for Romeo to be promoted, light would need to be absorbed not emitted) – which is only possible if the atom is NOT initially in its ground state, so that there will be an orbital at a lower energy level not fully occupied. That potentially complicates the model to be built.

For one thing, if the atom is not in its ground state, then atoms of elements of lower atomic mass than scandium might be the target atom to be modelled? Indeed, any atom from the element nitrogen (in the highly excited configuration 1s¹ 2s¹ 2p¹ 3s¹ 3p¹ 4s¹ 3d¹ ) on to zinc could theoretically have seven occupied energy levels. It did not help that there seemed to be no information on how many electrons were in this atom – four were specified, and we are told unspecified other 'family' members lived there, and two other characters were name-checked without it being explicit if they were also in the atom or just passing (from the local Abbey perhaps – would that be an atom of a noble gas?)

Interorbital distances?

As noted above, the authors refer to how they "delve into the concept of interatomic orbital distances", but this seems an oxymoron.

"From the analysis of the drawings, it emerges that the students' final drawings can be traced back to three different types of atom representation (R):

R1: orbits/orbitals represented at varying distances to convey the concept of energy levels more effectively;

R2: orbits/orbitals represented at correct distances according to the radius;

R3: attempt to depict the concept of orbitals and the correct distances between them."

Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

The authors refer to how in a figure assigned to category R3, "The distances between the spheres reflect the correct distances according to n²", but this does not strictly relate to an orbital model.

Orbitals do not have edges, so it is not possible to measure how far they are from anything. Strictly, every orbital reaches to infinity (even if the electron density soon gets so rare that it becomes effectively zero). The point is that this is a gradual falling-off and there is no sudden drop that we might think of as an edge.

Commonly orbitals are represented either with

probability contour lines, or
colour or shading showing differnt levels of electron density (i.e., the relative probabilities of an electron in the orbital being 'found' at different regions of the orbital), or
more simply with probability envelopes.

Those envelopes show where, say, 90% or 95% of the electron density is located – which means 10% or 5% of the electron density (that is inside the orbital) lies outside the envelope drawn. So, these lines are to soem degree arbitrary, conventional and do not correspond to anything physical ('real').

One could measure the distance between the centres of two different orbitals, but this would be a trivial issue when the orbitals are in the same atom. (That is, the atomic orbitals are all centred on the nucleus, so the centres have no distance between each other.)

This is different to a planetary type model where electrons are considered to be a certain distance from the nucleus, so the orbits have quantifiable radii. In moving to an orbital model we have to think of fuzzy overlapping volumes of space, and the notion of there being set distances between orbitals just does not work in this model.

Imagine being asked to report the distance between the soccer pitch and the hockey pitch.

And then imagine having that task when there are no marked out edges to the pitches.

The energy levels associated with the orbitals can be considered to have specific values, and so there are definite differences ('distances'?) between the levels in that sense – but these would be energy gaps: analogical 'distances' on an energy scale, not actual distances.

The authors suggest that,

Despite their discussion about orbitals, [for the students' final drawings] all groups drew orbits, representing them as lines depicting the trajectories of electrons
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

But that is not so clear from the diagrams of the models and the students' own comments.

Student 1: "In a circle, we drew lines. But we know that electrons don't follow that precise path; they exist in orbitals, which are regions where electrons are more likely to be found. So, we don't know the precise radius because it's a region. Therefore, in my opinion, since the radius can always vary, you can't use the radius to depict the atomic model; it's more accurate to use energy levels."

…

Teacher: "Here you have drawn the distances increasingly closer. Why?"

Student 2: "Because it represented differences in energy levels."
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

Some groups of students seem to have drawn concentric circles representing energy levels rather than orbits or shells or orbitals. Normally, energy level diagrams are not drawn like that, but this seems a perfectly reasonable form of representation providing it is explained.

Spherical orbitals

We also have to bear in mind that only s-orbitals have spherical symmetry. (A 'shell' of orbitals in an atom would be spherically symmetrical only if each orbital was singly or fully occupied. But it was not clear how many electrons were in this atom.)

The first seven energy levels in any atom or ion with more than one electron will be associated with p- and d-orbitals as well as s-orbitals. So, even if orbitals were represented with probability envelopes, and these were treated (incorrectly) as if the edges of the orbitals, then there would be no fixed 'distances' between the edges of any comparisons involving these non-spherical orbitals.

Not all orbitals have spherical geometry (Image by Smiley _p0p from Pixabay)

At this point it is interesting to examine the samples of student models represented in the paper. All of them are drawn with circles. The authors of the paper seemed satisfied with this aspect of the models.

Making sense of 486 nm and the 'THz 457s'

I pointed out above that my reading of the information given about the atom that it seemed the target atom could be from one of a wide range of elements. It seems I got this completely wrong,

We conclude this paper by highlighting a limitation of the story we have designed from a physical point of view. Our story does not fit the real atomic structure. Indeed, we chose to consider a hydrogen atom with multiple electrons because we thought it was easier for the students to manipulate. We are aware of the fact that this may represent a critical point of our story, but in the classes where we experienced the activity it has not created problems, since the students noticed this inconsistency and talked about it with the teacher.
Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024

Now, by definition, a model is never quite like what is modelled – or it ceases to be a model and becomes a perfect replica. But "a hydrogen atom with multiple electrons" is not an atom at all, but an ion. I am not clear why this is "easier to manipulate" than an atom of a different element, as in models of this kind the nucleus is in effect just a minute point charge – so its composition does not complicate the model in any significant way. If that nuclear charge is +7, say, rather than +1, it makes a difference, certainly (to energy levels), but that does not add any further complexity.

Perhaps the authors chose to retain a hydrogen nucleus because they wanted students to use data from hydrogen spectra? (But if so, this was a little naughty.)

The Balmer series

Again, it did not help that I did not know what the target knowledge set out in the curriculum was.⁴ But, knowing now that hydrogen was the target atom led me to suspect 486 nm and 457 THz radiation linked to lines in the hydrogen spectra – lines in the Balmer series associated with transitions between n=3 and n=2 (656 nm) and n=4 and n=2 (486 nm).

That was all very well, but those transitions referred to the hydogen atom and not to a hydrogen ion. The extra electrons repelling each other in the ion (assuming the ion could be considered stable, which is itself problematic) mean the energy levels (and so the energy gaps; and so the spectral lines) would all be different.

But, if we pretended the ion was stable, and if we pretended that the additional electrons did not change the energy levels (what is what I meant by being somewhat naughty), then the numbers made sense.

A sleight of hand?

Indeed, if we were to adopt the hydrogen atom as the model for our ion, then I sensed I understood why the orbitals were all drawn as circles. In the hydrogen atom, the energy levels are only associated with the principle quantum number. The 2p orbital is at just the same energy level as the 2s orbital. A transition from the N shell to the L shell has the same energy associated with, and so the same frequency of radiation, regardless of whether it involved 2s-4s or 2p-4s or 2s-4p or 2p-4p or 2s-4d or 2p-4d (or indeed 2s-4f or 2p-4f)⁵. That is a considerable simplification, that would make the task much easier for learners.

So, if we are modelling the hydrogen atomic energy levels, we only need to worry about the principle quantum number as there is one level for each value of n. The student diagrams reproduced in the paper suggested all the students understood the reference to an atom with seven energy levels to mean n (that is the principle quantum number related to 'shell') = 1-7.

But an energy level is not an orbital. The n=2 energy level in a hydrogen atom is associated with 4 orbitals, only one of which has spherical symmetry. The n=3 level is associated with 9 orbitals, only one of which has spherical symmetry.

Moreover, this assumption that all the orbtials in a shall are at the same energy level ('degenerate') only applies to a hydrogenic species (H, He⁺, Li²⁺, etc.) – that is, atom-like species with a single electron. The 'atom' (ion) with Romeo and Juliet and Mercutio and the nurse and the rest of the Capulets and Montagues (and possibly some clergy) would not have 2s and 2p orbitals that were degenerate. The presence of interacting electrons (repelling each other, that is, not lusting after each other and "quivering with love") would raze the degeneracy- so the 2s and 2p orbitals would actually be at different energy levels. And so also with 3s and 3p and 3d.

It is not the presence of a hydrogen nucleus which leads to degeneracy between the orbitals within each value of n (each shell), but a system of one nucleus and one electron. So if this 'atom' (ion) had seven energy levels, these would not equate to seven shells of electrons.

The model

So, it looks like the target model was an ion with a hydrogen nucleus, and 7 energy levels occupied by an unspecified number (>4) of electrons, which has the same energy structure and levels as a hydrogen atom, but where each energy level only contained an s orbital.

Models simplify, and in modelling we deliberately leave aside some complexity and nuance. However, we have to balance the gain in simplicity with the loss of authenticity.

A highly charged hydrogen ion could not exist (unless maintained by some very powerful external field)
Atoms have an infinite number of energy levels (but there is no harm in asking learners to ignore most of them for the time being when working on a task)
A hydrogen atom has orbitals of different types (s, p, d…) not all of which are of spherically symmetrical.
The electronic transitions in an ion would not be those found in the related atom, as energy levels of the system depend on the configuration of charges that are interacting. The ion would have many more potential transitions than a single-electron system (such as a hydrogen atom), and these would not have the same energies/frequencies/wavelengths as in the hydrogen atom.
Orbitals do not have edges, and they interpenetrate, so the concept of interatomic orbital distances does not correspond to anything 'realistic' in the orbital model of the atom.

So, the model seems to put aside a lot of the subtlety of the science. But then are these nuanced ideas suitable for treatment with most 15-16 year olds? I would have suspected not (which is why I started from a position of thinking this whole activity was somewhat ambitious), and that may well be why compromises were made in the teaching model adopted in this study.

But perhaps it would be better not to introduce an orbital model until we feel learners are ready to appreciate the quantum jump from concentric orbits to fuzzy, overlapping, infinitely-extended patterns of electronic probability, and the associated complex patterns of energy levels they generate. (But, again, the teaching model used may simply have been reflecting the target knowledge set out in the school curriculum in this particular national context? ⁴)

After all, as the authors had noted,

"Students do not clearly understand the concept of an orbital" (Aquilina, Dello Iacono, Gabelli, Picariello, Scettri & Termini, 2024)

Encouraging a new alternative conception?

To take one point. The 486 nm and 457 THz radiation is associated with transitions between n=3 and n=2 (656 nm) and n=4 and n=2 (486 nm) in the hydrogen atom, but NOT in the 'atom' populated with Montagues and Capulets.

Does this matter? After all, the point of the exercise is not to remember these specific values, but to be able to link radiation emitted or absorbed to electronic transitions – so, the particular values of 486 nm and 457 THz are irrelevant. True, but what students are potentially learning here is that the values of energy levels are not affected by the number of electrons repelling each other (here we have an ion with many electrons, but we can simply use the values for a hydrogen atom) – which is an alternative conception.

I also know that this is an alternative conception that learners are likely to readily develop. When students study ionisation energies, and make comparisons between different atoms, they often fail to allow for how the same designation of orbital does not imply an equivalence between differently populated electronic structures.

So, for example, a 2p orbital in an oxygen atom is not only not equivalent to a 2s orbital in the same atom: nor is it equivalent to a 2p orbital in a nitrogen atom. Nor, for that matter, is it entirely equivalent to a 2p orbital in the o^2- anion.

This is not the most serious alternative conception that students can acquire, but given the complexity and challenge of this whole topic area, it might be wise to avoid risk misleading students when possible.

Or am I just being over-critical because I myself found the task too challenging? ☹️

To see through an orbital clearly?

This was an interesting project, and I hope the authors explore the idea further, and perhaps use their experiences with this implementation to further refine the activity. But I am not sure it is helpful in the long term to encourage learners to work with a model that is so constrained that it is likely to encourage new alternative conceptions.

But would that be the case? If the activity is part of a dialogic teaching sequence and the catalyst for engaging students in a discussion of these abstract ideas – a discussion that the teacher carefully steers towards the canonical account – then perhaps the outcome can be more productive. I guess we can only conjecture about this, until someone investigates the long-term effects of learning from the activity.

As usual, it is fair to say "more research is needed".

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Work cited:

Aquilina, G.; Dello Iacono, U.; Gabelli, L.; Picariello, L.; Scettri, G.; Termini, G. "Romeo and Juliet: A Love out of the Shell": Using Storytelling to Address Students' Misconceptions and Promote Modeling Competencies in Science. Education Sciences, 2024, 14, 239. https://doi.org/10.3390/educsci14030239

Justi, R., & Gilbert, J. K. (2000). History and philosophy of science through models: some challenges in the case of 'the atom'. International Journal of Science Education, 22(9), 993-1009.

Taber, K. S. (1998) An alternative conceptual framework from chemistry education, International Journal of Science Education, 20 (5), pp.597-608.
[Download paper]

Taber, K. S. (2002) Conceptualizing quanta – illuminating the ground state of student understanding of atomic orbitals, Chemistry Education: Research and Practice in Europe, 3 (2), pp.145-158 [Download paper]

Taber, K. S. (2019). The Nature of the Chemical Concept: Constructing chemical knowledge in teaching and learning. Royal Society of Chemistry.

Taber, K. S. and Watts, M. (1996) The secret life of the chemical bond: students' anthropomorphic and animistic references to bonding, International Journal of Science Education, 18 (5), pp.557-568. [Downlod paper]

Notes

¹ Of course there are many atoms, and indeed many kinds of atoms – so the use of the definite article ('the') is strictly inappropriate. But, this is common usage,

What seems potentially more problematic is the use of the definitive article when the referent is not a specific individual specimen. Chemistry teachers will say things like "the ammonia molecule is pyramidal" when no ammonia molecule is either specified directly or can be inferred to be the case in point from the context. This probably does not seem problematic for the simple reason that it does not matter which ammonia molecule is being referred to: they are all pyramidal. So, statements such as the ammonia molecular is pyramidal; the chlorine atom readily accepts an electron; the K shell is nearest the nucleus; and the iodide ion is a good leaving group; etcetera, will be true regardless.

These statements 'work' in a way that some apparently parallel statements from outside of chemistry would not: the house has a blue door, the man walks with a limp, the baby sneezed all night, the bicycle has squeaky brakes, etcetera. Some houses have blue doors – many do not…So, we should not say 'the house has a blue door' unless we have made it clear which house we are referring to. Yet, we do not need to say which particular water molecule is polar, as they all are (i.e., it may be considered an essential quality of a water molecule). So, the question here is why a teacher would say 'the ammonia molecule is pyramidal' when they are not actually referring to a particular specimen, and the point they are making is actually that (all) ammonia molecules are pyramidal.
Taber, 2019, p.128

And, even if we can refer to 'the carbon atom' when we mean any and all carbon atoms, to simply refer to 'the atom' seems a slight to the periodic table – surely we need to say which (kind of) atom we are modelling? That point certainly proved to be critical in the context of the modelling task discussed in this article!

² The force is symmetrical – the same magnitude force acts on the nucleus and the electron, with each being pulled towards the other. Students commonly have alternative conceptions about this such as thinking the force only acts in one direction (from nucleus to electron) or that the force on the electron is greater.

Read about Newton's third law and common alternative conceptions

³ In the planetary model of the atoms, electrons moved in orbits. In the orbital model we can think of electrons moving about the orbital, and the 'electron density' as a kind of average over time of where they have been. However, it may be more in keeping with the quantum model of the atom to suggest the electrons do not actually move around but rather have probabilities of being located at different points under conditions of observation. (According to a very common interpretation of quantum theory, the notion of an electron being somewhere specific only makes sense at the point of observation.) This is pretty difficult to appreciate (especially for most school-age learners), and I suspect most chemists are happy enough most of the time to think of the electrons moving around in their orbitals.

⁴ Five of the six authors, including the corresponding author, were based in Italy (the other author gave an affiliation based in Canada), so I assume the schools from which the work is reported is in Italy. The paper reports the task set and the student responses in English, so it is not clear if English was used as the language of instruction in the school (this seems unlikely unless this was an International School, but the paper does not report that material has been translated into English).

⁵ 4f orbitals are not usually relevant to atomic structure till we consider cerium, element 58. But the familiar order of filling orbitals as we imagine we are building up atoms (1s < 2s < 2p< 3s < 3p < 4s < 3d < 4p… *) refers to species with more than one electron. For a hydrogen atom, a 4f orbtial is at the same energy level as the 4s orbital, as when occupied the atom's electron, neither would be sheilded at all from the nucleus by other electrons.

(* Ironically, the familiar descriptions of the discrete orbitals designated in this way are based on calculations for a hydrogen atom and do not strictly apply to multi-electron atoms. However the moodel generally works well, and is widely used.)

Occidently re-orienting atoms

It seems atoms are not quite as chemists imagine them not to be

Keith S. Taber

A research paper presenting a new model of atomic and molecular structure was recently brought to my attention. ¹

'New Atomic Model with Identical Electrons Position in the Orbital's and Modification of Chemical Bonds and MOT [molecular orbital theory]' ² is published in a recently-launched journal with the impressive title of Annals of Atoms and Molecules. This is an open-access journal available free on the web – so readily accessible to chemistry experts, as well as students studying the subject and lay-people looking to learn from a scholarly source. [Spoiler alert – it may not be an ideal source for scholarly information!]

In the paper, Dr Morshed proposes a new model of the atom that he suggests overcomes many problems with the model currently used in chemistry.

A new model of atomic structure envisages East and West poles as well as North and South poles) (Morshed, 2020a, p.8)

Of course, as I have often pointed out on this blog, one of the downsides of the explosion in on-line publishing and the move to open access models of publication, is that anyone can set up as an academic journal publisher and it can be hard for the non-expert to know what reflects genuine academic quality when what gets published in many new journals often seems to depend primarily upon an author being willing to pay the publisher a hefty fee (Taber, 2013).

That is not to suggest open-access publishing has to compromise quality: the well-established, recognised-as-prestigious journals can afford to charge many hundreds of pounds for open-access publication and still be selective. But, new journals, often unable to persuade experienced experts to act as reviewers, will not attract many quality papers, and so cannot be very selective if they are to cover costs (or indeed make the hoped-for profits for their publishers).

A peer reviewed journal

The journal with the impressive title of Annals of Atom and Molecules has a website which explains that

"Annals of Atoms and Molecules is an open access, peer reviewed journal that publishes novel research insights covering but not limited to constituents of atoms, isotopes of an element, models of atoms and molecules, excitations and de-excitations, ionizations, radiation laws, temperatures and characteristic wavelengths of atoms and molecules. All the published manuscripts are subjected to standardized peer review processing".
https://scholars.direct/journal.php?jid=atoms-and-molecules

So, in principle at least, the journal has experts in the field critique submissions, and advise the editors on (i) whether a manuscript has potential to be of sufficient interest and quality to be worth publishing, and (ii) if so, what changes might be needed before publications is wise.

Read about peer review

Standardised peer review gives the impression of some kind of moderation (perhaps renormalisation given the focus of the journal? ³) of review reports, which would involve a lot of extra work and another layer of administration in the review process…but I somehow suspect this claim really just meant a 'standard' process. This does not seem to be a journal where great care is taken over the language used.

Effective peer review relies on suitable experts taking on the reviewing, and editors prepared to act on their recommendations. The website lists five members of the editorial board, most of whom seem to be associated with science departments in academic institutions:

Prof. Farid Menaa (Fluorotronics Inc) ⁴
Prof. Sabrin Ragab Mohamed Ibrahim (Department of Pharmacognosy and Pharmaceutical chemistry, Taibah University)
Prof. Mina Yoon (Department of Physics and Astronomy, University of Tennessee)
Dr. Christian G Parigger (Department of Physics, University of Tennessee Space Institute)
Dr. Essam Hammam El-Behaedi (Department of Chemistry and Biochemistry, University of North Carolina Wilmington)

The members of a journal Editorial Board will not necessarily undertake the reviewing themselves, but are the people entrusted by the publisher with scholarly oversight of the quality of the journal. For this journal it is claimed that "Initially the editorial board member handles the manuscript and may assign or the editorial staff may assign the reviewers for the received manuscript". This sounds promising, as at least (it is claimed) all submissions are initially seen by a Board member, whether or not they actually select the expert reviewers. (The 'or' means that the claim is, of course, logically true even if in actuality all of the reviewers are assigned by the unidentified office staff.)

At the time of writing only three papers have been published in the Annals. One reviews a spectroscopic method, one is a short essay on quantum ideas in chemistry – and then there is Dr Morshed's new atomic theory.

A new theory of atomic structure

The abstract of Dr Morshed's paper immediately suggests that this is a manuscript which was either not carefully prepared or has been mistreated in production. The first sentence is:

The concept of atom has undergone numerous changes in the history of chemistry, most notably the realization that atoms are divisible and have internal structure Scientists have known about atoms long before they could produce images of them with powerful magnifying tools because atoms could not be seen, the early ideas about atoms were mostly founded in philosophical and religion-based reasoning.
Morshed, 2020a, p.6

Presumably, this was intended to be more than one sentence. If the author made errors in the text, they should have been queried by the copy editor. If the production department introduced errors, then they should have been corrected by the author when sent the proofs for checking. Of course, a few errors can sometimes still slip through, but this paper has many of them. Precise language is important in a research paper, and sloppy errors do not give the reader confidence in the work being reported.

The novelty of the work is also set out in the abstract:

In my new atomic model, I have presented the definite position of electron/electron pairs in the different orbital (energy shells) with the identical distance among all nearby electron pairs and the degree position of electrons/electron pairs with the Center Point of Atoms (nucleus) in atomic structure, also in the molecular orbital.
Morshed, 2020a, p.6

This suggests more serious issues with the submission than simple typographical errors.

Orbital /energy shells

The term "orbital (energy shells)" is an obvious red flag to any chemist asked to evaluate this paper. There are serious philosophical arguments about precisely what a model is and the extent to which a model of the atom might be considered to be realistic. Arguably, models that are not mathematical and which rely on visualising the atom are inherently not realistic as atoms are not the kinds of things one could see. So, terms such as shell or orbital are either being used to refer to some feature in a mathematical description or are to some extent metaphorical. BUT, when the term shell is used, it conventionally means something different from an orbital.

That is, in the chemical community, the electron shell (sic, not energy shell) and the orbital refer to different classes of entity (even if in the case of the K shell there is only one associated orbital). Energy levels are related, but again somewhat distinct – an energy level is ontologically quite different to an orbital or a shell in a similar way to how sea level is very different in kind to a harbour or a lagoon; or how 'mains voltage' is quite different from the house's distribution box or mains ring; or how an IQ measurement is a different kind of thing to the brain of the person being assessed.

Definite positions of electrons

An orbital is often understood as a description of the distribution of the electron density – we might picture (bearing in mind my point that the most authentic models are mathematical) the electron smeared out as in a kind of time-lapse representation of where the electron moves around the volume of space designated as an orbital. Although, as an entity small enough for quantum effects to be significant (a 'quanticle'? – with some wave-like characteristics, rather than a particle that is just like a bearing ball only much smaller), it may be better not to think of the electron actually being at any specific point in space, but rather having different probabilities of being located at specific points if we could detect precisely where it was at any moment.

That is, if one wants to consider the electron as being at specific points in space then this can only be done probabilistically. The notion of "the definite position of electron/electron pairs in the different orbital" is simply nonsensical when the orbital is understood in terms of a wave function. Any expert asked to review this manuscript would surely have been troubled by this description.

It is often said that electrons are sometimes particles and sometimes waves but that is a very anthropocentric view deriving from how at the scale humans experience the world, these seem very distinct types of things. Perhaps it is better to think that electrons are neither particles nor waves as we experience them, but something else (quanticles) with more subtle behavioural repertoires. We think that there is a fundamental inherent fuzziness to matter at the scale where we describe atoms and molecules.

So, Dr Morshed wants to define 'definite positions' for electrons in his model, but electrons in atoms do not have a fixed position. (Later there is reference to circulation – so perhaps these are considered as definite relative positions?) In any case, due to the inherent fuzziness in matter, if an electron's position was known absolutely then there would would (by the Heisenberg uncertainty principle) be an infinite uncertainty in its momentum, so although we might know 'exactly' where it was 'now' (or rather 'just now' when the measurement occurred as it would take time for the signal to be processed through first our laboratory, and then our nervous, apparatus!) this would come with having little idea where it was a moment later. Over any duration of time, the electron in an atom does not have a definite position – so there is little value in any model that seeks to represent such a fixed position.

The problem addressed

Dr Morshed begins by giving some general historical introduction to ideas about the atom, before going on to set out what is argued to be the limitation of current theory:

Electrons are arranged in different orbital[s] by different numbers in pairs/unpaired around the nuclei. Electrons pairs are associated by opposite spin together to restrict opposite movement for stability in orbital rather angular movements. The structural description is obeyed for the last more than hundred years but the exact positions of electrons/pairs in the energy shells of atomic orbital are not described with the exact locations among different orbital/shells.
Morshed, 2020a, p.6

Some of this is incoherent. It may well be that English is not Dr Morshed's native language, in which case it is understandable that producing clear English prose may be challenging. What is less forgivable is that whichever of Profs. Ibrahim, Yoon, or Drs Menaa, Parigger, or El-Behaedi initially handled the manuscript did not point out that it needed to be corrected and in clear English before it could be considered for publication, which could have helped the author avoid the ignominy of having his work published with so many errors.

That assumes, of course, that whichever of Ibrahim, Yoon, Menaa, Parigger, or El-Behaedi initially handled the manuscript were so ignorant of chemistry to be excused for not spotting that a paper addressing the issue of how current atomic models fail to assign "exact positions of electrons/pairs in the energy shells of atomic orbital are not described with the exact locations among different orbital/shells" both confused distinct basic atomic concepts and seemed to be criticising a model of atomic structure that students move beyond before completing upper secondary chemistry. In other words, this paper should have been rejected on editorial screening, and never should have been sent to review, as its basic premise was inconsistent with modern chemical theory.

If, as claimed, all papers are seen by the one of the editorial board, then the person assigned as handling editor for this one does not seem to have taken the job seriously. (And as only three papers have been published since the journal started, the workload shared among five board members does not seem especially onerous.)

Just in case the handling editorial board member was not reading the text closely enough, Dr Morshed offered some images of the atomic model which is being critiqued as inadequate in the paper:

A model of the atom criticised in the paper in Annals of Atoms and Molecules (Morshed, 2020a, p.7)

I should point out that I am able to reproduce material from this paper as it is claimed as copyright of the author who has chosen to publish open access with a license that "permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited". (Although, if you look very closely at the first figure, it seems to have superimposed in red text "© Copyright www.chemistrytutotial.org", where, by an unlikely coincidence, I found what seems to be the same image on the page Atomic Structure with Examples.)

Read about copyright in academic works

Again, the handling editor should have noticed that these images in the figure reflect the basic model of the atom taught in introductory school classes as commonly represented in simple two-dimensional images. These are not the models used to progress knowledge in academic chemistry today.

These images are not being reproduced in the research paper as part of some discussion of atomic representations in school textbooks. Rather this is the model that the author is suggesting falls short as part of current chemical theory – but it is actually an introductory pedagogical model that is not the basis of any contemporary chemical research, and indeed has not been so for the best part of a century. Even though the expression "the electrons/electron pairs position is not identical by their position, alignments or distribution" does not have any clear meaning in normal English, what is clear is that these very simple models are only used today for introductory pedagogic purposes.

Symmetrical atoms?

The criticism of the model continues:

The existing electrons pair coupling model is not also shown clearly in figure by which a clear structure of opposite spine pair can be drowned. Also there are no proper distribution of electron/s around the center (nuclei) to maintain equal number of electrons/electronic charge (charge proportionality) around the total mass area of atomic circle (360°) in the existing atomic model (Figure 1). There are no clear ideas about the speed proportion and time of circulation of electrons/electron pairs in the atomic orbital/shells so there is no answer about the possibility of uneven number of electrons/electron pairs at any position /side of atomic body can arise that must make any atom unstable.
Morshed, 2020a, p.7

Again, this makes little sense (to me at least – perhaps the Editorial Board members are better at hermeneutics than I am). Now we are told that electrons are 'circulating' in the orbitals/shell which seems inconsistent with them having the "definite positions" that Dr Morshed's model supposedly offers. Although I can have a guess at some of the intended meaning, I really would love to know what is meant by "a clear structure of opposite spine pair can be drowned".

Protecting an atom from drowning? (Images by Image by ZedH and Clker-Free-Vector-Images from Pixabay)

A flat model of the atom

I initially thought that Dr Morshed is concerned that the model shown in figure 1 cannot effectively show how in the three dimensional atomic structure the electrons must be arranged to give a totally symmetric patterns: and (in his argument) that this would be needed else it would leave the atoms unstable. Of course, two dimensional images do not easily show three dimensional structure. So when Dr Morshed referred to the "atomic circle (360°) in the existing atomic model" I assumed he was actually referring to the sphere.

On reflection, I am not so sure. I was unimpressed by the introduction of cardinal points for the atom (see Dr Morshed's figure 2 above, and figure 4 below). I could understand the idea of a nominal North and South pole in relation to the angular momentum of the nucleus and electrons 'spinning up or down' – but surely the East and West poles are completely arbitrary for an atom as any point on the 'equator' could be used as the basis for assigning these poles. However, if Dr Morshed is actually thinking in terms of a circular (i.e., flat) model of the atom, and not circular representations of a spherical model of atomic structure then atoms would indeed have an Occident and an Orient! The East pole WOULD be to the right when the atom has the North pole at the top as is conventional in most maps today. ⁵

But atoms are not all symmetrical?

But surely most atoms are not fully symmetrical, and indeed this is linked to why most elements do not commonly exist as discrete atoms. The elements of those that do, the noble gas elements, are renown for not readily reacting because they (atypically for atoms) have a symmetrical electronic 'shield' for the nuclear charge. However, even some of these elements can be made cold enough to solidify – as the van der Waals forces allow transient fluctuating dipoles. So the argument seems to be based on a serious alternative conception of the usual models of atomic structure.

It is the lack of full symmetry in an atom of say, fluorine, or chlorine, which means that although it is a neutral species it has an electron affinity (that is, energy is released when the anion is formed) as an electron can be attracted to the core charge where it is not fully shielded.

The reference to "time of circulation of electrons/electron pairs in the atomic orbital/shells" seems to refer to a mechanical model of orbital motion, which again, has no part in current chemical theory.

Preventing negative electron pairs repelling each other

Dr Morshed suggests that the existing model of atomic structure cannot explain

Why the similar charged electrons don't feel repulsion among themselves within the same nearby atomic orbital of same atom or even in the molecular orbital when two or more atomic orbital come closer to form molecular orbital within tinier space though there is more possibility of repulsion between similar charged electrons according to existing atomic model.
Morshed, 2020a, p.7

Electrons do not feel repulsion for the same reason they do not feel shame or hunger or boredom – or disdain for poor quality journals. Electrons are not the kind of objects that can feel anything. However, this anthropomorphic expression is clearly being used metaphorically.

I think Dr Morshed is suggesting that the conventional models of atomic structure do not explain why electrons/electron pairs do not repel each other. Of course, they do repel each other – so there is no need to look for an explanation. This then seems to be an alternative conception of current models of the atom. (The electrons do not get ejected from the atom as they are also attracted to the nucleus – but, if they did not repel each other, there would be no equilibrium of forces, and the structure of the atom would not be stable.)

A new model of atomic structure supposedly reflects the 'proper' angles between electrons in atoms (Morshed, 2020, p.9)

Dr Morshed suggests that his model (see his Figure 4) 'proves the impossibility of repulsion between any electron pairs' – even those with similar charges. All electron pairs have negative (so similar) charges – it is part of the accepted definition of an electron that is is a negatively charged entity. I do not think Dr Morshed is actually suggesting otherwise, even if he thinks the electrons in different atoms have different magnitudes of negative charge (Morshad, 2020b).

Dr Morshed introduces a new concept that he calls 'center of electron pairs neutralization point'.

This is the pin-point situated in a middle position between two electrons of opposite spin pairs. The point is exactly between of opposite spine electron pairs so how the opposite electronic spin is neutralized to remaining a stable electron pair consisting of two opposite spin electrons. This CENP points are assumed to be situated between the cross section of opposite spine electronic pair's magnetic momentum field diameter (Figure 3).
Morshed, 2020a, p.8

The yellow dot represents a point able to neutralise the opposite spin of a pair of electrons(!), and is located at the point found by drawing a cross from the ends of the ⥯ symbols used to show the electron spin! This seems to be envisaged a real point that has real effects, despite being located in terms of the geometry of a totally arbitrary symbol.

So, the electron pair is shown as a closely bound pair of electrons with the midspot of the complex highlighted (yellow in the figure) as the 'center of electron pairs neutralization point'. Although the angular momentum of the electrons with opposite spin leads to a magnetic interaction between them, they are still giving rise to an electric field which permeates through the space around them. Dr Morshed seems to be suggesting that in his model there is no repulsion between the electron pairs. He argues that:

According to magnetic attraction/repulsion characteristics any similar charges repulse or opposite charges attract when the charges energy line is in straight points. If similar charged or opposite charged end are even close but their center of energy points is not in straight line, there will be no attraction or repulsion between the charges (positive/negative). Similarly, when electrons are arranged in energy shells around the nucleus the electrons remain in pairs within opposite spin electrons where the poses a point which represent as the center of repulsion/attraction points (CENP) and two CENP never come to a straight within the atomic orbital so the similar charged electrons pairs don't feel repulsion within the energy shells.
Morshed, 2020a, pp.8-9

A literal reading of this makes little sense as any two charges will always have their centres in a straight line (from the definition of a straight line!) regardless of whether similar or opposite charges or whether close or far apart.

My best interpretation of this (and I am happy to hear a better one) is that because the atom is flat, and because the electron pairs have spin up and spin down electrons, with are represented by a kind of ⥮ symbol, the electrons in some way shield the 'CENP' so that the electron pair can only interact with another charge that has a direct line of sight to the CENP.

Morshed seems to be suggesting that although electron pairs are aligned to allow attractions with the nucleus (e.g., blue arrows) any repulsion between electron pairs is blocked because an electron in the pair shields the central point of the pair (e.g., red arrow and lines)

There are some obvious problems here from a canonical perspective, even leaving aside the flat model of the atom. One issue is that although electrons are sometimes represented as ↿ or ⇂ to indicate spin, electrons are not actually physically shaped like ↿. Secondly, pairing allows electrons to occupy the same orbital (that is, have the same set of principal, azimuthal and magnetic quantum numbers) – but this does not mean they are meant to be fixed into a closely bound entity. Also, this model works by taking the idea of spin direction literally, when – if we do that – electrons can have only have spin of ±¹/₂. In a literal representation such as used by Dr Morshed he would need to have ALL his electrons orientated vertically (or at least all at the same angle from the vertical). So, the model does not work in its own terms as it would prevent most of the electron pairs being attracted to the nucleus.

Morshed's figure 4 'corrected' given that electrons can only exist in two spin states. In the (corrected version of the representation of the) Morshed model most electron pairs would not be attracted to the nucleus.

A new (mis)conception of ionic bonding

Dr Morshed argues that

In case of ionic compound formation problem with the existing atomic model is where the transferred electron will take position in the new location on transferred atom? If the electrons position is not proportionally distributed along total 360 circulating area of atom, then the position of new transferred electron will cause the polarity in every ion (both cation and anion forms by every transformation of electrons) so the desired ionization is not possible thus every atom (ion) would become dipolar. On the point of view any ionization would not possible i.e., no ionic bonded compound would have formed.
Morshed, 2020, p.7

Again, although the argument may have been very clear to the author, this seems incoherent to a reader. I think Dr Morshed may be arguing that unless atoms have totally symmetrical electrons distributions ("proportionally distributed along total 360 circulating area of atom") then when the ion is formed it will have a polarity. Yet, this seems entirely back to front.

If the atom to be ionised was totally symmetric (as Dr Morshed thinks it should be), then forming an ion from the atom would require disrupting the symmetry. Whereas, by contrast, in the current canonical model, we assume most atoms are not symmetrical, and the formation of simple ions leads to a symmetric distribution of electrons (but unlike in the noble gas atoms, a symmetrical electron distribution which does not balance the nuclear charge).

Dr Morshad illustrates his idea:

Ionic bond formation represented by an non-viable interaction between atoms (Morshed, 2020, p.10)

Now these images show interactions between discrete atoms (a chemically quite unlikely scenario, as discrete atoms of sodium and chlorine are not readily found) that are energetically non-viable. As has often been pointed out, the energy released when the chloride ion is formed is much less than the energy required to ionise the sodium atom, so although this scheme is very common on the web and in poor quality textbooks, it is a kind of chemical fairy tale that does not relate to any likely chemical context. (See, for example, Salt is like two atoms joined together.)

The only obvious difference between these two versions of the fairly tale (if we ignore that in the new version both protons and neutrons appear to be indicated by + signs which is unhelpful) seems to be that the transferred electron changes its spin for some reason that does not seem to be explained in the accompanying text. The explanation that is given is

My new atomic model with identical electrons pair angle position is able to give logical solution to the problems of ion/ionic bond formation. As follows: The metallic atom which donate electrons during ion formation from outermost orbital, the electrons are arranged maintaining definite degree angle around 360° atomic mass body shown in (Figure 4). After the transformation the transferred electron take position at the vacant place of the transferred atoms outermost orbital, then instant the near most electrons/pairs rearrange their position in the orbital changing their angle position with the CPA [central point of the atom, i.e., the nucleus] due to electromagnetic repulsion feeling among the similar charged electrons/pairs. Thus the ionic atom gets equal electron charge density around whole of their 360° atomic mass body resulting the cation and anion due to the positive and negative charge difference in atomic orbital with their respective nucleus. Thus every ion becomes non polar ion to form ionic bond within two opposite charged ion (Figure 5).
Morshed, 2020, p.9

So, I think, supposedly part (b) of Dr Morshed's figure 5 is meant to show, better than part (a), how the electron distribution is modified when the ion is formed. It would of course be quite possible to show this in the kind of representations used in (a), but in any case it does not look any more obvious in (b) to my eye!

So, figure 5 does not seem to show very well Dr Morshed's solution to a problem I do not think actually exists in the context on a non-viable chemical process. Hm.

Finding space for the forces

Another problem with the conventional models, according to Dr Morshed, is that, as suggested in his figures 6 and 7 is that the current models do not leave space for the 'intermolecular' [sic, intramolecular] force of attraction in covalent bonds.

In current models, according to Morshed's paper, electrons get in the way of the covalent bond (Morshed, 2020, p.11)

Dr Morshad writes that

According to present structural presentation of shared paired electrons remain at the juncture of the bonded atomic orbital, if they remain like such position they will restrict the Inter [sic] Molecular Force (IMF) between the bonded atomic nuclei because the shared paired electron restricts the attraction force lying at the straight attraction line of the bonded nuclei the shown in (Figure 6a).
Morshed, 2020, p.11

There seem to be several alternative conceptions operating here – reflecting some of the kind of confusions reported in the literature from studies on students' ideas.

Just because the images are static two dimensional representations, this does not mean electrons are envisaged to be stationary at some point on a shell;
and just because we draw representations of atoms on flat paper, this does not mean atoms are flat;
The figure is meant to represent the bond, which is an overall configuration of the nuclei and the electrons, so there is not a distinct intramolecular force operating separately;
Without the electrons there would be no "Inter [sic] Molecular Force (IMF) between the bonded atomic nuclei" as the nuclei repel each other: the bonding electrons do not restrict the intramolecular force (blocking it, because they lie between the nuclei), but are crucial to it existing.

Regarding the first point here, Dr Morshed suggests

Covalent bonds are formed by sharing of electrons between the bonded atoms and the shared paired electrons are formed by contribution of one electron each of the participating atoms. The shared paired electrons remain at the overlapping chamber (at the juncture of the overlapped atomic orbital).
Morshed, 2020, p.9

That is, according to Dr Morshed's account of current atomic theory, in drawing overlapping electron shells, the electrons of the bond which are 'shared' (and that is just a metaphor, of course) are limited to the area shown as overlapping. This is treating an abstract and simplistic representation as if it is realistic. There is no chamber. Indeed, the molecular orbital formed by the overlap of the atomic orbitals will 'allow' the electrons to be likely to be found within quite a (relatively – on an atomic scale) large volume of space around the bond axis. Atomic orbitals that overlap to form molecular orbitals are in effect replaced by those molecular orbitals – the new orbital geometry reflects the new wavefunction that takes into account both electrons in the orbital.

So, if there has been overlap, the contributing atomic orbitals should be considered to have been replaced (not simply formed a chamber where the circles overlap), except of course Dr Morshed 's figures 6 and 7 show shells and do not actually represent the system of atomic orbitals.

Double bonds

This same failure to interpret the intentions and limitation of the simplistic form of representation used in introductory school chemistry leads to similar issues when Dr Morshed considers double bonding.

A new model of atomic structure suggests an odd geometry for pi bonds (Morshed, 2020, p.12)

Dr Morshed objects to the kind of representation on the left in his figure 8 as two electron pairs occupy the same area of overlap ('chamber'),

It is shown for an Oxygen molecule; two electron shared pairs are formed and take place at the overlapping chamber result from the outermost orbital of two bonded Oxygen atoms. But in real séance [sic?] that is impossible because two shared paired electrons cannot remain in a single overlapping chamber because of repulsion among each pairs and among individual electrons.
Morshed, 2020, p.12.

Yet, in the model Dr Morshed employs he had claimed that electron pairs do not repel unless they are aligned to allow a direct line of sight between their CNPs. In any case, the figure he criticises does not show overlapping orbitals, but overlapping L shells. He suggests that the existing models (which of course are not models currently used in chemistry except in introductory classes) imply the double bond in oxygen must be two sigma bonds: "The present structure of O₂ molecule show only two pairs of electron with head to head overlapping in the overlapping chamber i.e., two sigma bond together which is impossible" (p.12).

However, this is because a shell type presentation is being used which is suitable for considering whether a bond is single or double (or triple), but no more. In order to discuss sigma and pi bonds with their geometrical and symmetry characteristics, one must work with orbitals, not shells. ⁶

Yet Dr Morshed has conflated shells and orbitals throughout his paper. His figure 8a that supposedly shows "Present molecular orbital structural showing two shared paired electrons in the same overlapped chamber" does not represent (atomic, let alone molecular) orbitals, and is not intended to suggest that the space between overlapping circles is some kind of chamber.

"The remaining two opposite spin unpaired electrons in the two bonded [sic?] Oxygen's outer- most orbital [sic, shell?] getting little distorted towards the shared paired electrons in their respective atomic orbital then they feel an attraction among the opposite spin electrons thus they make a bond pairs by side to side overlapping forms the pi-bond"
Morshed, 2020, p.12.

It is not at all clear to see how this overlap occurs in this representation (i.e., 8b). Moreover, the unpaired electrons will not "feel an attraction" as they are both negatively charged even if they have anti-parallel spins. The scheme also makes it very difficult to see how the pi bond could have the right symmetry around the bond axis, if the 'new molecular orbital structure' was taken at face value.

Conclusion

Dr Morshed's paper is clearly well meant, but it does not offer any useful new ideas to progress chemistry. It is highly flawed. There is no shame in producing highly flawed manuscripts – no one is perfect, which is why we have peer review to support authors in pointing out weaknesses and mistakes in their work and so allowing them to develop their ideas till they are suitable for publication. Dr Morshed has been badly let down by the publishers and editors of Annals of Atoms and Molecules. I wonder how much he was charged for this lack of service? ⁷

Publishing a journal paper like this, which is clearly not ready to make a contribution to the scholarly community through publication, does not only do a disservice to the author (who will have this publication in the public domain for anyone to evaluate) but can potentially confuse or mislead students who come across the journal. Confusing shells with orbitals, misrepresenting how ionic bonds form, implying that covalent bonds are due to a force between nuclei, suggesting that electron pairs need not repel each other, suggesting a flat model of the atom with four poles… there are many points in this paper that can initiate or reinforce student misconceptions.

Supposedly, this manuscript was handled by a member of the editorial board, sent to peer reviewers and the publication decision based on those review reports. It is hard to imagine any peer reviewer who is actually an academic chemist (let alone an expert in the topics published in this journal) considering this paper would be publishable, even with extensive major revisions. The whole premise of the paper (that simple representations of atoms with concentric shells of electrons reflect the models of atomic and molecular structure used today in chemistry research) is fundamentally flawed. So:

were there actually any reviews? (Really?)
if so, were the reviews carried out by experts in the field? (Or even graduate chemists or physicists?)
were the reviews positive enough to justify publication?

If the journal feels I am being unfair, then I am happy to publish any response submitted as a comment below.

Dr Menaa, Prof. Ibrahim, Prof. Yoon, Dr Parigger, Dr El-Behaedi…

If you were the Board Member who handled this submission and you feel my criticisms are unfair, please feel free to submit a comment. I am happy to publish your response.

Or, if you were not the Board Member who (allegedly) handled this submission, and would like to make that clear…

Works cited:

Gilbert, W. (1600/2016). On the Magnet, Magnetic Bodies, and the Great Magnet of the Earth. A new science, with many both arguments and experiment proofs. (V. Wilmont, Trans.): Lulu.com.
Morshed, A. M. A. (2020a). New Atomic Model with Identical Electrons Position in the Orbital's and Modification of Chemical Bonds and MOT. Annals of Atoms and Molecules, 2(1), 6-13.
Morshed, A. M. A. (2020b) Electrons Charge Magnitudes (ECM) are Dissimilar for Different Mass Atoms'. https://www.researchgate.net/project/Electrons-Charge-MagnitudesECM-are-Dissimilar-for-Different-Mass-Atoms
Taber, K. S. (2013, 29th November). Challenges to academic publishing from the demand for instant open access to research. Chinese Social Sciences Today, p. A06.

Note:

¹ I thank Professor Eric Scerri of UCLA for bringing my attention to the deliciously named 'Annals of Atoms and Molecules', and this specific contribution.

² That is my reading of the abbreviation, although the author uses the term a number of times before rather imprecisely defining it: "Similar solution can be made for molecular orbital (MOT) as such as: The molecular orbital (MO) theory…" (p.10).

³ Renormalisation is the name given to a set of mathematical techniques used in areas such as quantum field theory when calculations give implausible infinite results in order to 'lose' the unwanted infinities. Whilst this might seem like cheating – it is tolerated as it works very well.

⁴ I was intrigued that 'Prof.' Farid Menaa seemed to work for a non-academic institution, as generally companies cannot award the title of Professor. Of course, Prof. Meena may also have an appointment at a university that partners the company, or could have emeritus status having retired from academia.

I found him profiled on another publisher's site as "Professor, Principal Investigator, Director, Consultant Editor, Reviewer, Event Organizer and Entrepreneur,…" who had worked in oncology, dermatology, haemotology (when "he pioneered new genetic variants of stroke in sickle cell anemia patients" which presumably is much more positive than it reads). Reading on, I found he had 'followed' complementary formations in "Medecine [sic], Pharmacy, Biology, Biochemistry, Food Sciences and Technology, Marine Biology, Chemistry, Physics, Nano-Biotechnology, Bio-Computation, and Bio-Statistics" and was "involved in various R&D projects in multiple areas of medicine, pharmacy, biology, genetics, genomics, chemistry, biophysics, food science, and technology". All of which seemed very impressive (nearly as wide a range of expertise as predatory journal publishers claim for me), but made me none the wiser about the source of his Professorial title.

⁵ Today. Although interestingly, in the first major comprehensive account of magnetism, Gilbert (1600/2016) tended to draw the North-South axis of the earth horizontally in his figures.

⁶ The representations we draw are simple depictions of something more subtle. If the circles did represent orbitals then they could not show the entire volume of space where the electron might be found (as this is theoretically infinite) but rather an envelope enclosing a volume where there is the highest probability (or 'electron density'). So orbitals will actually overlap to some extent even when simple images suggest otherwise.

⁷ I wonder because the appropriate page, https://scholars.direct/publication-charges.php, "was not found on this server" when I looked to see.

Move over Mendeleev, here comes the new Mendel

Seeking the islets of Filipenka Henadzi

Keith S. Taber

"new chemical elements with atomic numbers 72-75 and 108-111 are supposedly revealed, and also it is shown that for heavy elements starting with hafnium, the nuclei of atoms contain a larger number of protons than is generally accepted"
Henadzi, 2019, p.2

Somehow I managed to miss a 2019 paper bringing into doubt the periodic table that is widely used in chemistry. It was suggested that many of the heavier elements actually have higher atomic numbers (proton numbers) than had long been assumed, with the consequence that when these elements are correctly re-positioned it reveals two runs of elements that should be in the periodic table, but which till now have not been identified by chemists.

According to Henadzi we need to update the periodic table and look for eight missing elements (original image by Image by Gerd Altmann from Pixabay)

Henadzi (2019) suggests that "I would like to name groups of elements with the numbers 72-75 and 108-111 [that is, those not yet identified that should have these numbers], the islets of Filipenka Henadzi."

The orginal Mendeleev

This is a bit like being taken back to when Dmitri Mendeleev first proposed his periodic table and had the courage to organise elements according to patterns in their properties, even though this left gaps that Mendeleev predicted would be occupied by elements yet to be discovered. The success of (at least some) of his predictions is surely the main reason why he is considered the 'father' of the periodic table, even though others were experimenting with similar schemes.

Now it has been suggested that we still have a lot of work to do to get the periodic table right, and that the version that chemists have used (with some minor variations) for many decades is simply wrong. This major claim (which would surely be considered worthy of the Nobel prize if found correct) was not published in Nature or Science or one of the prestigious chemistry journals published by learned societies such as the Royal Society of Chemistry, but in an obscure journal that I suspect many chemists have never heard of.

The original Mendel

This is reminiscent of the story of Mendel's famous experiments with inheritance in pea plants. Mendel's experiments are now seen as seminal in establishing core ideas of genetics. But Mendel's research was ignored for many years.

He presented his results at meetings of the Natural History Society of Brno in 1865 and then published them in a local German language journal – and his ideas were ignored. Only after other scientists rediscovered 'his' principles in 1900, long after his death, was his work also rediscovered.

Moreover, the discussion of this major challenge to accepted chemistry (and physics if I have understood the paper) is buried in an appendix of a paper which is mostly about the crystal structures of metals. It seems the appendix includes a translation of work previously published in Russian, explaining why, oddly, a section part way through the appendix begins "This article sets out the views on the classification of all known chemical elements, those fundamental components of which the Earth and the entire Universe consists".

Calling out 'predatory' journals

I have been reading some papers in a journal that I believed, on the basis of its misleading title and website details, was an example of a poor-quality 'predatory journal'. That is, a journal which encourages submissions simply to be able to charge a publication fee (currently $1519, according to the website), without doing the proper job of editorial scrutiny. I wanted to test this initial evaluation by looking at the quality of some of the work published.

One of the papers I decided to read, partly because the topic looked of particular interest, was 'Nature of Chemical Elements' (Henadzi, 2019). Most of the paper is concerned with the crystal structures of metals, and presenting a new model to explain why metals have the structure they do. This is related to the number of electrons per atom that can be considered to be in the conduction band – something that was illustrated with a simple diagram that unfortunately, to my reading at least, was not sufficiently elaborated.¹

The two options referred to seem to refer to n-type (movement of electrons) and p-type (movement of electrons that can be conceptualised as movement of a {relatively} positive hole, as in semi-conductor materials) – Figure 1 from Henadzi, 2019: p2

However, what really got my attention was the proposal for revising the periodic table and seeking eight new elements that chemists have so far missed.

Beyond Chadwick

Henadzi tells readers that

"The innovation of this work is that in the table of elements constructed according to the Mendeleyev's law and Van-den- Broek's rule [in effect that atomic number in the periodic table = proton number], new chemical elements with atomic numbers 72-75 and 108-111 are supposedly revealed, and also it is shown that for heavy elements starting with hafnium, the nuclei of atoms contain a larger number of protons than is generally accepted. Perhaps the mathematical apparatus of quantum mechanics missed some solutions because the atomic nucleus in calculations is taken as a point."
Henadzi, 2019, p.4

Henadzi explains

"When considering the results of measuring the charges of nuclei or atomic numbers by James Chadwick, I noticed that the charge of the core of platinum is rather equal not to 78, but to 82, which corresponds to the developed table. For almost 30 years I have raised the question of the repetition of measurements of the charges of atomic nuclei, since uranium is probably more charged than accepted, and it is used at nuclear power plants."
Henadzi, 2019, p.4

Now Chadwick is most famous for discovering the neutron – back in 1932. So he was working a long time ago, when atomic theory was still quite underdeveloped and with apparatus that would seem pretty primitive compared with the kinds of set up used today to investigate the fundamental structure of matter. That is, it is hardly surprising if his work which was seminal nearly a century ago had limitations. Henadzi however seems to feel that Chadwick's experiments accurately reveal atomic numbers more effectively than had been realised.

Sadly, Henadzi does not cite any specific papers by Chadwick in his reference list, so it is not easy to look up the original research he is discussing. But if Henadzi is suggesting that data produced almost a century ago can be interpreted as giving some elements different atomic numbers to those accepted today, the obvious question is what other work, since, establishes the accepted values, and why should it not be trusted. Henadzi does not discuss this.

Explaining a long-standing mystery

Henadzi points out that whereas for the lighter elements the mass number is about twice the atomic number (that is, the number of neutrons in a nucleus approximately matches the number of protons) as one proceeds through the period table this changes such the ratio of protons:neutrons shifts to give an increasing excess of neutrons. Henadzi also implies that this is a long standing mystery, now perhaps solved.

"Each subsequent chemical element is different from the previous in that in its core the number of protons increases by one, and the number of neutrons increases, in general, several. In the literature this strange ratio of the number of neutrons to the number of protons for any the kernel is not explained. The article proposes a model nucleus, explaining this phenomenon."
Henadzi, 2019, p.5

Now what surprised me here was not the pattern itself (something taught in school science) but the claim that the reason was not known. My, perhaps simplistic, understanding is that protons repel each other because of their similar positive electrical charges, although the strong nuclear force binds nucleons (i.e., protons and neutrons collectively) into nuclei and can overcome this.

Certainly what is taught in schools is that as the number of protons increases more neutrons are needed to be mixed in to ensure overall stability. Now I am aware that this is very much an over-simplification, what we might term a curriculum model or teaching model perhaps, but what Henadzi is basically suggesting seems to be this very point, supplemented by the idea that as the protons repel each other they are usually found at the outside of the nucleus alongside an equal number of neutrons – with any additional neutrons within.

The reason for not only putting protons on the outer shell of a large nucleus in Henadzi's model seems to relate to the stability of alpha particles (that is, clumps of two protons and two neutrons, as in the relatively stable helium nucleus). Or, at least, that was my reading of what is being suggested,

"For the construction of the [novel] atomic nucleus model, we note that with alpha-radioactivity of the helium nucleus is approximately equal to the energy.

Therefore, on the outer layer of the core shell, we place all the protons with such the same number of neutrons. At the same time, on one energy Only bosons can be in the outer shell of the alpha- particle nucleus and are. Inside the Kernel We will arrange the remaining neutrons, whose task will be weakening of electrostatic fields of repulsion of protons."
Henadzi, 2019, p.5

The lack of proper sentence structure does not help clarify the model being mooted.

Masking true atomic number

Henadzi's hypothesis seems to be that when protons are on the surface of the nucleus, the true charge, and so atomic number, of an element can be measured. But sometimes with heavier elements some of the protons leave the surface for some reason and move inside the nucleus where their charge is somehow shielded and missed when nuclear charge is measured. This is linked to the approximation of assuming that the charge on an object measured from the outside can be treated as a point charge.

This is what Henadzi suggests:

"Our nuclear charge is located on the surface, since the number of protons and the number of neutrons in the nucleus are such that protons and neutrons should be in the outer layer of the nucleus, and only neutrons inside, that is, a shell forms on the surface of the nucleus. In addition, protons must be repelled, and also attracted by an electronic fur coat. The question is whether the kernel can be considered a point in the calculations and up to what times? And the question is whether and when the proton will be inside the nucleus….if a proton gets into the nucleus for some reason, then the corresponding electron will be on the very 'low' orbit. Quantum mechanics still does not notice such electrons. Or in other words, in elements 72-75 and 108-111, some protons begin to be placed inside the nucleus and the charge of the nucleus is screened, in calculations it cannot be taken as a point."
Henadzi, 2019, p.5

So, I think Henadzi is suggesting that if a proton gets inside the nucleus, its associated electron is pulled into a very close orbit such that what is measured as nuclear charge is the real charge on the nucleus (the number of protons) partially cancelled by low lying electrons orbiting so close to the nucleus that they are within what we might call 'the observed nucleus'.

This has some similarity to the usual idea of shielding that leads to the notion of core charge. For example, a potassium atom can be modelled simplistically for some purposes as a single electron around a core charge of plus one (+19-2-8-8) as, at least as a first approximation, we can treat all the charges within the outermost N (4th) electron shell (the 19 protons and 18 electrons) as if a single composite charge at the centre of the atom. ²

Dubious physics

Whilst I suspect that the poor quality of the English and the limited detail included in this appendix may well mean I am missing part of the argument here, I am not convinced. Besides the credibility issue (how can so many scientists have missed this for so long?) which should never be seen as totally excluding unorthodox ideas (the same thing could have been asked about most revolutionary scientific breakthroughs) my understanding is that there are already some quite sophisticated models of nuclear structure which have evolved alongside programmes of emprical research and which are therefore better supported than Henadzi's somewhat speculative model.

I must confess to not understanding the relevance of the point charge issue as this assumption/simplification would seem to work with Henadzi's model – from well outside the sphere defined by the nucleus plus low lying electrons the observed charge would be the net charge as if located at a central point, so the apparent nuclear charge would indeed be less than the true nuclear charge.

But my main objection would be the way electrostatic forces are discussed and, in particular, two features of the language:

Naked protons

protons must be repelled, and also attracted by an electronic fur coat…

I was not sure what was meant by "protons must be repelled, and also attracted by an electronic fur coat". The repulsion between protons in the nucleus is balanced by the strong nuclear force – so what is this electronic 'fur coat'?

This did remind me of common alternative conceptions that school students (who have not yet learned about nuclear forces) may have, along the lines that a nucleus is held together because the repulsion between protons is balanced by their attraction to the ('orbiting') electrons. Two obvious problems with this notion are that

the electrons would be attracting protons out of the nucleus just as they are repelling each other (that is, these effects reinforce, not cancel), and
the protons are much closer to each other than to the electrons, and the magnitude of force between charges diminishes with distance.

Newton's third law and Coulomb's law would need to be dis-applied for an electronic effect to balance the protons' mutual repulsions. (On Henadzi's model the conjectured low lying electrons are presumably orbiting much closer to the nucleus than the 1s electrons in the K shell – but, even so, the proton-electron distance will be be much greater than the separation of protons in the nucleus.)³

But I may have misunderstood what Henadzi's meant here by the attraction of the fur coat and its role in the model.

A new correspondence principle?

if a proton gets into the nucleus for some reason, then the corresponding electron will be on the very 'low' orbit

Much more difficult to explain away is the suggestion that "if a proton gets into the nucleus for some reason, then the corresponding electron will be on the very 'low' orbit". Why? This is not explained, so it seems assumed readers will simply understand and agree.

In particular, I do not know what is meant by 'the corresponding electron'. This seems to imply that each proton in the nucleus has a corresponding electron. But electrons are just electrons, and as far as a proton is concerned, one electron is just like any other. All of the electrons attract, and are attracted by, all of the protons.

Confusing a teaching scheme for a mechanism?

This may not always be obvious to school level students, especially when atomic structure is taught through some kind of 'Aufbau' scheme where we add one more proton and one more electron for each consecutive element's atomic structure. That is, the hydrogen atom comprises of a proton and its 'corresponding' electron, and in moving on to helium we add another proton, with its 'corresponding' electron and some neutrons. These correspond only in the sense that to keep the atom neutral we have to add one negative charge for each positive charge. They 'correspond' in a mental accounting scheme – but not in any physical sense.

That is a conceptual scheme meant to do pedagogic work in 'building up' knowledge – but atoms themselves are just systems of fundamental particles following natural laws and are not built up by the sequential addition of components selected from some atomic construction kit. We can be misled into mistaking a pedagogic model designed to help students understand atomic structure for a representation of an actual physical process. (The nuclei of heavy elements are created in the high-energy chaos inside a star – within the plasma where it is too hot for them to capture the electrons needed to form neutral atoms.)

A similar category error (confusing a teaching scheme for a mechanism) often occurs when teachers and textbook authors draw schemes of atoms combining to form molecules (e.g., a methane molecule formed from a carbon atom and four hydrogen atoms) – it is a conceptual system to work with the psychological needs for students to have knowledge built up in manageable learning quanta – but such schemes do not reflect viable chemical processes.⁴

It is this kind of thinking that leads to students assuming that during homolytic bond fission each atom gets its 'own' electron back. It is not so much that this is not necessarily so, as that the notion of one of the electrons in a bond belonging to one of the atoms is a fiction.

The conservation of force conception (an alternative conception)

When asked about ionisation of atoms it is common for students to suggest that when an electron is removed from an atom (or ion) the remaining electrons are attracted more strongly because the force for the removed electron gets redistributed. It is as if within an atom each proton is taking care of attracting one electron. In this way of thinking a nucleus of a certain charge gives rise to a certain amount of force which is shared among the electrons. Removing an electron means a greater share of the force for those remaining. This all seems intuitive enough to many learners despite being at odds with basic physical principles (Taber, 1998).

I am not deducing that Henadzi, apparently a retired research scientist, shares these basic misconceptions found among students. Perhaps that is the case, but I would not be so arrogant as to diagnose this just from the quoted text. But that is my best understanding of the argument in the paper. If that is not what is meant, then I think the text needs to be clearer.

The revolution will not be televised…

In conclusion, this paper, published in what is supposedly a research journal, is unsatisfactory because (a) it makes some very major claims that if correct are extremely significant for chemistry and perhaps also physics, but (b) the claims are tucked away in an appendix, are not fully explained and justified, and do not properly cite work referred to; and the text is sprinkled with typographic errors, and seems to reflect alternative conceptions of basic science.

I very much suspect that Henadzi's revolutionary ideas are just wrong and should rightly be ignored by the scientific community, despite being published in what claims to be a peer-reviewed (self-describing 'leading international') research journal.

However, perhaps Henadzi's ideas may have merit – the peer reviewers and editor of the journal presumably thought so – in which case they are likely to be ignored anyway because the claims are tucked away in an appendix, are not fully explained and justified, and do not properly cite work referred to; and the text is sprinkled with typographic errors, and seems to reflect alternative conceptions of basic science. In this case scientific progress will be delayed (as it was when Mendel's work was missed) because of the poor presentation of revolutionary ideas.

How does the editor of a peer-reviewed journal move to a decision to publish in 4 days?

Let down by poor journal standards

So, either way, I do not criticise Henadzi for having and sharing these ideas – healthy science encompasses all sorts of wild ideas (some of which turn out not to have been so wild as first assumed) which are critiqued, tested, and judged by the community. However, Henadzi has not been well supported by the peer review process at the journal. Even if peer reviewers did not spot some of the conceptual issues that occurred to me, they should surely have noticed the incompleteness of the argument or at the very least the failures of syntax. But perhaps in order to turn the reviews around so quickly they did not read the paper carefully. And perhaps that is how the editor, Professor Nour Shafik Emam El-Gendy of the Egyptian Petroleum Research Institute, was able to move to a decision to publish four days after submission.⁵

If there is something interesting behind this paper, it will likely be missed because of the poor presentation and the failure of peer review to support the author in sorting the problems that obscure the case for the proposal. And if the hypothesis is as flawed as it seems, then peer review should have prevented it being published until a more convincing case could be made. Either way, this is another example of a journal rushing to publish something without proper scrutiny and concern for scientific standards.

Works cited

Henadzi, F. (2019). Nature of Chemical Elements. Journal of Chemistry: Education Research and Practice, 3(1), 1-5.
Taber, K. S. (1998) The sharing-out of nuclear attraction: or I can't think about Physics in Chemistry, International Journal of Science Education, 20 (8), pp.1001-1014. [Download the paper]
Taber, K. S. (2013). Upper Secondary Students' Understanding of the Basic Physical Interactions in Analogous Atomic and Solar Systems. Research in Science Education, 43(4), 1377-1406. doi:10.1007/s11165-012-9312-3

Footnotes:

¹ My understanding of the conduction band in a metal is that due to the extensive overlap of atomic orbitals, a great many molecular orbitals are formed, mostly being quite extensive in scope ('delocalised'), and occurring with a spread of energy levels that falls within an energy band. Although strictly the molecular orbitals are at a range of different levels, the gaps between these levels are so small that at normal temperatures the 'thermal energy' available is enough for electrons to readily move between the orbitals (whereas in discrete molecules, with a modest number of molecular orbitals available, transitions usually require absorption of higher energy {visible or more often} ultraviolet radiation). So, this spread of a vast number of closely spaced energy levels is in effect a continuous band.

Given that understanding I could not make sense of these schematic diagrams. They SEEM to show the number of conduction electrons in the 'conduction band' as being located on, and moving around, a single atom. But I may be completely misreading this – as they are meant to be (cross sections through?) a tube.

"we consider a strongly simplified one- dimensional case of the conduction band. Option one: a thin closed tube, completely filled with electrons except one. The diameter of the electron is approximately equal to the diameter of the tube. With such a filling of the zone, with the local movement of the electron, there is an opposite movement of the "place" of the non-filled tube, the electron, that is, the motion of a non-negative charge. Option two: in the tube of one electron – it is possible to move only one charge – a negatively charged electron"
Henadzi, 2019, p.2

² The shell model is a simplistic model, and for many purposes we need to use more sophisticated accounts. For example, the electrons are not strictly in concentric shells, and electronic orbitals 'interpenetrate' – so an electron considered to be in the third shell of an atom will 'sometimes' be further from the nucleus than an electron considered to be in the fourth shell. That is, a potassium 4s electron cannot be assumed to be completely/always outside of a sphere in which all the other atomic electrons (and the nucleus) are contained, so the the core cannot be considered as a point charge of +1 at the nucleus, even if this works as an approximation for some purposes. The effective nuclear charge from the perspective of the 4s electron will strictly be more than +1 as the number of shielding electrons is somewhat less than 18.

³ Whilst the model of electrons moving around the nucleus in planetary orbits may have had some heuristic value in the development of atomic theory, and may still be a useful teaching model at times (Taber, 2013), it seems it is unlikely to have the sophistication to support any further substantive developments to chemical theory.

⁴ It is very common for learners to think of chemistry in terms of atoms – e.g., to think of atoms as starting points for reactions; to assume that ions must derive from atoms. This way of thinking has been called the atomic ontology.

⁵ I find it hard to believe that any suitably qualified and conscientious referees would not raise very serious issues about this manuscript precluding publication in the form it appears in the journal. If the journal really does use peer review, as is claimed, one has to wonder who they think suitable to act as expert reviewers, and how they persuade them to write their reports so quickly.

Based on this, and other papers appearing in the journal, I suspect one of the following:

a) peer review does not actually happen, or

b) peer review is assigned to volunteers who are not experts in the field, and so are not qualified to be 'peers' in the sense intended when we talk of academic peer review, or

c) suitable reviewers are appointed, but instructed to do a very quick but light review ignoring most conceptual, logical, technical and presentation issues as long as the submission is vaguely on topic, or

di) appropriate peer reviewers are sought, but the editor does not expect authors to address reviewer concerns before approving publication, or possibly

dii) decisions to publish sub-standard work are made by administrators without reference to the peer reviews and the editor's input

A tangible user interface for teaching fairy tales about chemical bonding

Once upon a time there was a nometal atom that was an electron short of a full outer shell. "I wish I had an octet" she said, "if only I knew a nice metal atom that might donate their extra electron to me"… Image by S. Hermann & F. Richter from Pixabay

an invitation to read — Once upon a time there was a nometal atom that was an electron short of a full outer shell. "I wish I had an octet" she said, "if only I knew a nice metal atom that might donate their extra electron to me"… Image by S. Hermann & F. Richter from Pixabay

So this account is a mixture of the generally correct; the potentially misleading; and the downright wrong.

Agrawal and colleagues describe an ingenuous apparatus they had put together so that students can physically manipulate tokens to see ionic bond formation represented. This looks like something that younger secondary children would really enjoy.

They also report a small-scale informal evaluation of a classroom test of the apparatus with an unspecified number of students, reporting very positive responses. The children generally found the apparatus easy to use, the information it represented easy to understand, and they thought it helped them learn about chemical [ionic] compound formation. So this seems very successful.

However, what did it help them learn?

The teaching model

"For example, when a token representing [a] sodium atom is placed on the table top, its valence shell (outermost shell) with 1 revolving valence electron is displayed around the token. When the student places a chlorine atom on the table, its valence shell along with 7 revolving valence electrons is displayed. The electron from the sodium atom gets transferred to the chlorine atom. +1 charge appears on the sodium atom due to loss of electron and -1 charge appears on the chlorine atom due to gain of electron. Both form a stable compound. The top bar on the user interface turns green to show success and displays the name of the stable compound so formed (sodium chloride, in this case). The valence shell of the atoms also turns green to show a stable compound."

Agrawal et al., 2013 (no page numbers)

Which sounds impressive, except NaCl is not formed by electron transfer, and with the ChemicAble the resulting structure is a single Na⁺-Cl^– ion pair, which does not represent the structure of the NaCl compound, and indeed would not be a stable structure.

Does it matter if children are taught scientific fairy tales?

The innovation likely motivated learners. And the authors seem to be basing their 'ChemicAble' on the curriculum models set out in the model science books produced by the Indian National Council of Educational Research and Training. So, the authors have produced something that helps children learn the science curriculum in that context,and so presumably what students will subsequently be examined on. Given that, it seems churlish to point out that what is being taught is scientifically wrong.

So, I find it hard to be critical of the authors, but I do wonder why governments want children to learn scientific fairy tales that are nonsense. The electron transfer model of ionic bonding seems to be popular with teachers, and received well by learners, so if the aim of education is to find material to teach that we can then test children on (so they can be graded, rated, sequences, selected), what is the problem? After all, I am a strong advocate for the idea that what we teach in school science is usually, necessarily, a simplification of the science – and indeed is basically a set of models – and not some absolute account of the universe.

Here the children, the teacher and the researchers have all put a lot of effort into helping learners acquire a scientifically incorrect account of ionic bonding. We think children should learn about the world at the molecular, naometre scale as this is such an important part of chemistry as a science. Yet, to my mind, if we are going to ask children to put time and effort into learning abstract models of the structure of nature at submicroscopic levels, even though we know this is challenging for them, then, although we need to work with simplified models, these should at least be intellectually honest models, and not accounts that we know are completely inauthentic and do not reflect the science. This is why I have been so critical of the incoherence and errors in the chemistry in the English National Curriculum (Taber, 2020).

Otherwise, education is reduced to a game for its own sake, and we may as well ask students to learn random Latin texts, or the plots of Grimms' Fairy Tales, or even the chemical procedures obscured by disguised reagents and allegorical language in alchemical texts, and then test them on how much they retain.

Actually, no, this learning of false models is worse than that, because learning these incorrect accounts confuses students and impedes their learning of the canonical scientific models if they later go on to study the subject further. So, if it is important that children learn something about ionic bonding, let's teaching something that is scientifically authentic and stop offering fairly tales about atoms wanting to fill their shells.

Sources cited:

Agrawal, M., Jain, M., Luthra, V., Thariyan, A., & Sorathia, K. (2013). ChemicAble: Tangible interaction approach for learning chemical bonding. Paper presented at the Proceedings of the 11th Asia Pacific Conference on Computer Human Interaction.
Butts, B., & Smith, R. (1987). HSC Chemistry Students' Understanding of the Structure and Properties of Molecular and Ionic Compounds. Research in Science Education, 17(1), 192-201.
Taber, K. S. (1994). Misunderstanding the Ionic Bond. Education in Chemistry, 31(4), 100-103.
Taber, K. S. (1997). Student understanding of ionic bonding: molecular versus electrostatic thinking? School Science Review, 78(285), 85-95.
Taber, K. S. (2013). A common core to chemical conceptions: learners' conceptions of chemical stability, change and bonding. In G. Tsaparlis & H. Sevian (Eds.), Concepts of Matter in Science Education (pp. 391-418). Dordrecht: Springer.
Taber, K. S. (2020). Conceptual confusion in the chemistry curriculum: exemplifying the problematic nature of representing chemical concepts as target knowledge. Foundations of Chemistry, 22, 309-334. doi:https://doi.org/10.1007/s10698-019-09346-3

If you take all of the electrons off an atom, then it would not be matter

Keith S. Taber

The notion that atoms are the smallest components of matter has a strong historical pedigree – but the modern idea of the atom is unlike the solid and indivisible (= atomos: uncuttable) elementary particles imagined by some Greek philosophers. Modern atoms are considered complex structures, and may be dismantled.

It is not unusual for students to suggest that atom is the smallest thing that one can get, and then go on to describe atomic structure in terms of smaller components! The idea that the atom is the smallest thing possible (a kind of motto or slogan) is commonly adopted and then retained despite learning about subatomic particles.

Mohammed, however, justified his suggestion that an atom was "the smallest amount of matter you can get" by arguing that "matter is something that is built out of protons, neutrons and electrons". So Mohammed's notion of what counted as 'matter' (an ontological question) was at odds with the scientific account

Mohammed did not suggest that matter had to have overall neutrality, and his suggestion that matter is something that is built out of protons, neutrons and electrons had to be amended when he realised it would exclude hydrogen atoms as being matter:

So what if I had a balloon full of hydrogen gas, would that, would the hydrogen be matter?
Yeah.
So would that consist of protons, neutrons and electrons?
No it wouldn't. Sorry, can I take away the neutrons
Okay, so matter's what then? What's our new definition of matter?
Protons, electrons.

Mohammed presented his responses with confidence and without hesitation, which seemed to suggest he was offering well established ideas. However, he did not seem to have fully thought through these ideas, and perhaps was constructing a rationale in situ in the interview. The logical consequences of Mohammed's new definition was that atoms and ions would be considered matter but not nuclei or electrons.

What if I had sodium. Do you think that would be matter?… if I had a lump of sodium, would that be matter?
Yeah
And why is that matter?
Because it has, it has a full atom, it has protons, neutrons, electrons, even though you can have no neutrons.
Okay, but it has to have the protons and the electrons?
Yeah.
Now what if I just had one atom of sodium, would that still be matter?
Yeah.
…so let's say I've got my atom, with my eleven protons, and my probably twelve neutrons I think usually. And I've got eleven electrons round the outside. If I take take one of the electrons off this atom, it's not an atom any more is it?
It's an ion.
Now is it still matter?
Yeah.
Because I've still got protons and electrons. What if I took a second electron off, could I take a take second electron off?
Yeah.
What have I got then, then?
You've still got matter.
What if I took a third one off?
Well if you, if you just take all of them off, then you'd stop having matter.
So if I've got eleven electrons, can I take ten of them off?
Yeah.
And I'd still have matter?
Yeah.

The idea of what counts as matter here seems a rather idiosyncratic alternative conception (rather than being a common alternative conception that is widely shared). Science teachers would probably consider that all material (sic) particles are matter, and – perhaps – that this should be obvious to students. However, the submicroscopic realm is far from everyday experience so perhaps it is not surprising that students often form their own alternative conceptions.

Electrons repel each other, keeping them out of the nucleus

Keith S. Taber

Brian was a participant in the Understanding Chemical Bonding project. He was interviewed during the first year of his college 'A level' course (equivalent to Y12 of the English school system). Brian was shown, and asked about, a sequence of images representing atoms, molecules and other sub-microscopic structures of the kinds commonly used in chemistry teaching. He was shown a simple representation of an atom which he identified as showing "electron configuration…of an element, sodium".

Brian identified the electrons and nucleus, and was asked about the arrangement of the electrons:

Can you tell me why the electrons stay there, in these positions, why they don't fly off into space?
'Cause they're held by the nucleus.
In what way does the nucleus hold them, any idea?
It's got a positive charge, and so attracts the electrons, which are negatively charged.
Okay, so, it's got an electrical attraction there.
Yeah.
Why don't they just go into the nucleus then, if they're attracted, why don't they just get pulled into the nucleus?
Because, 'cause there's more than one electron, they repel each other, and keep them out.
Ah, so what about these ones [on opposite sides of the nucleus] though, these repel each other do they, even though they
Yeah.
are drawn on opposite sides?
Yeah.
So that's what stops them actually falling into the nucleus, that they repel each other?
Yeah.

It seems that Brian recognised electrical interaction between the nucleus and the electrons in an atomic structure. He also recognised that electrons would repel each other, but did not seem to have considered that in itself that was an insufficient explanation for the structure of the atom (as, for example, the sole electron in a hydrogen atom does not fall into the nucleus).

Although Brian's explanation was based on sound principles (negative electrons repel each other), it is an alternative conception. Coulombic forces are proportional to charges and diminish with separation – inspection of the figure should suggest that the two inner electrons (tending to be pushed inwards by outer electrons) at least must experience net force towards the nucleus.

The stability of atoms – the failure of electrons to spiral into the nucleus leading to atoms collapsing – was one of the phenomena which led to the development of quantum theory. In classical physics the stability of electron orbits was a puzzle to be solved, as orbiting electrons 'should' have acted as electrical oscillators, and emitted energy as their orbits decayed into the nucleus whilst the atom (very quickly) collapsed. Quantum theory posited limited allowed energy states, rather than a continuum of possibilities – but learners new to the topic do not know about this.

Often learners simply accept atomic structure when presented with planetary-system type representations of the atom. 'Quanticles' such as atoms are so far from direct human experience that they presumably seem strange enough such that questions that might seem obvious to a teacher do not arise for students. (Students also commonly accept the 'atom is like a tiny solar system' teaching analogy, and may map inappropriately between the two systems.)

Do the forces from the outer shells push the protons and the neutrons together?

Keith S. Taber

Annie was a colearner (participant) in the Understanding Chemical Bonding project. In her first interview, during the first year of her two year 'A level' college course, Annie was asked about a (Bohr type) representation of a (sodium) atom. Annie did not know what held the protons and neutrons together in the atomic nucleus, but suggested it might be due to forces from the electrons "pushing":

Interviewer: Can you identify the different parts of that diagram? What's the blob in the centre?
Annie: It's the nucleus.
I: That's the nucleus. Do you know what's in the nucleus?
A: The protons and, no the electrons and the neutrons, no the protons and the neutrons. The electrons are round the outside.
I: There's protons and neutrons in the centre okay.
A: Yeah.
I: Erm, what holds them together, any idea?
A: Is it the forces from the outer ring? Outer rings or outer shells? The electronic forces?
I: What repelling them in? Holding them
A: Yeah.
I: in the centre? It could be.
A: Pushing them.
I: It's not actually, but that's a sensible suggestion. So you haven't actually done anything about what holds the nucleus together?
A: No.
…

The question of why the nucleons should be held together (given the repulsion between positive protons) is not usually considered in school chemistry lesson, and does not seem to be a question which students tend to spontaneously consider. The interview continued…

I: What holds the electrons in place?
(pause, c.4s)
A: Er (pause, c.9s) Not really sure, but I know there's a set pattern of how many can go in each shell, so if its connected with that?
I: Huh hm, do you think, do you think you need anything to hold the electrons in place, or I mean is it just the way the Universe is, or God's will, or, you know, or just aesthetic, you know nature's aesthetic,
A: Yeah.
I: and it looks pretty? I mean do you think there has to be some physical reason why the electrons are there rather than anywhere else?
A: Probably is to do with the structure of it.
I: But you are not, you're not sure why,
A: No.
I: it should be that the electrons should be in orbitals or orbits?
A: No.
I: Rather than just scattered higgledy-piggledy.
A: No, I don't know that.

In this section of the interview, Annie seems to suggest she is not aware of any forces acting on the electrons, and suggests it may be something inherent in the electronic structure which holds the electrons in place. It seems odd that Annie does not invoke a force from the nucleus, given her comment just earlier about a possible pushing from the outer electron ring/shell onto the nucleons. It seems Annie does not know about, or at least does not bring to mind, an electrical force attracting the electrons and nucleus. However, this was tested by a slightly different question…

Okay. So can you tell me why the electrons don't fall out of the atom? I mean if you imagine that this was sort of, er, an atom that's placed vertically, why don't the electron's just fall out of the bottom?
A: The forces hold them together.
I: What kind of forces are they. Do you know?
(pause, c.5s)
A: The attraction from the nucleus, from the protons.
I: So the protons in the nucleus attract the electrons?
A: Yeah.
I: So what kind of attraction is that. What kind of force is that?
A: Er (pause, c.7s) I don't know

So Annie is aware that the electrons are attracted by the nucleus, and specifically by the protons. Despite this, Annie does not suggest the interaction is electronic, or specially refer to charge. Her suggestion that the outer electron shell may push on the nucleus, holding it together, contradicts Newton's third law in that forces between bodies are either attractive or repulsive, not not a mixture of the two. So if the nucleus attracts electrons, then electrons must attract (not push) the nucleus. Annie's suggestion was also inconsistent with the way forces between charges depend upon separation (by an inverse square law): the repulsion between adjacent protons would be far larger than any force due to the more distant electrons.

An atom is the smallest amount of matter you can get

Keith S. Taber

Mohammed was a participant in the Understanding Science Project. When Mohammed was near the end of his first term of upper secondary science (in Y10) he told me that in his chemistry lessons he had been studying atoms and ionic bonding. When I asked him what an atom was, he suggested it was "the smallest amount of matter you can get" as well as being "it's the building block of all matter". It is not unusual for students to suggest that atom is the smallest thing that one can get, and then go on to report that it has smaller constituent parts when asked about atomic structure! Mohammed justified his suggestion that an atom was "the smallest amount of matter you can get" by excluding individual subatomic particles from being considered matter:

I: So – if I ask you, what's an atom?
M: It's the smallest amount of matter you can get, it's the building block of all matter.
I: So you can't get anything smaller?
M: No. If, if you – if I, let's say, took the electrons away, then it wouldn't be matter any more.
I: What would it be then, then?
M: It would just be a nucleus.
I: So, if we have got an atom, and you take the electrons away, that would seem to be smaller than the atom? But you are saying it is not really matter any more, it does not count as matter.
M: Yeah.
I: So how do we know what's matter? What's matter?
M: Matter is something that is built out of protons, neutrons and electrons.
I: Ah, so it has to have all three?
M: Yeah.

So from Mohammed's perspective it would not necessarily have been inconsistent to suggest that an atom was the smallest particle of matter possible, despite it having structure, if the definition of matter included suitable criteria. However, Mohammed did not suggest that, for example, matter had to have overall neutrality, and his suggestion that matter is something that is built out of protons, neutrons and electrons had to be amended when it was then tested out. He maintained, however, that if you take all of the electrons off an atom, then you would stop having matter.*

Curriculum statement	Commentary
"…the electrons present in the outermost shell of an atom are known as the valence electrons."	Fine
"The outermost shell of an atom can accommodate a maximum of 8 electrons."	This is only correct for period 2. It is false false for period 1 (2 electrons), period 3 (18 electrons), period 4 (32 electrons), etcetera.
"Atoms of elements, having a completely filled outermost shell show little chemical activity. Of these inert elements, the helium atom has two electrons in its outermost shell and all other elements have atoms with eight electrons in the outermost shell."	Fine – apart from the reference to "completely filled outermost shell" Of the noble gases, only helium and neon have full outer shells. 'Atoms' of the heavier noble gases with full outer shells would not atoms, but ions, and these would be extremely unstable – i.e., they could not exist except hypothetically under extreme conditions of very intense electrical fields.
"The combining capacity of the atoms of other elements is explained as an attempt to attain a fully-filled outermost shell (8 electrons forming an octet). The number of electrons gained, lost or shared so as to make the octet of electrons in the outermost shell, gives us directly the combining capacity of the element called the valency."	Hm – generally the valency can be identified with the difference between an atom's electronic configuration and the 'nearest' noble gas electronic configuration – which would be an octet of valence shell electrons, except in period one. However, the equivalence suggested here "a fully-filled outermost shell (8 electrons forming an octet)" is only true for period 2. An octet does not suffice for a full outer shell in period 3 (full at 18 electrons), or in period 4 (full at 32 electrons), etcetera. And, in the statement, valency is described as being related to the intentions of atoms: "is explained as an attempt to attain…" (and "…electrons gained, lost or shared so as to…") which encourages student misconceptions. [Read about 'Learners' anthropomorphic thinking'.]
"An ion is a charged particle and can be negatively or positively charged. A negatively charged ion is called an 'anion' and the positively charged ion, a 'cation'. Metals generally form cations and non-metals generally form anions."	Fine.
"Atoms have tendency to complete their octet by this give and take of electron forming compounds."	This is a common notion, but actually suspect. Some elements have an electron affinity such that the atoms would tend to pick up an electron spontaneously. However, for an element with a valency of -2, such as oxygen, once it has become a singly charged anion (O^–), it will not attract a second electron, so apart from the halogens, this is misleading. The negatively charged O^– ion will indeed spontaneously repel/be repelled by a (negatively charged) electron. Metallic elements have ionisation enthalpies showing that energy has to be applied to strip electrons from them – they certainly do not have a "tendency to complete their octet by this giv[ing]" of electrons.
"Compounds that are formed by electron transfer from metals to non-metals are called ionic compounds."	This is not usually how ionic compounds are formed. Although it is possible in the lab. to use binary synthesis (e.g., burning sodium in chlorine – not for the faint-hearted), that is not how ionic compounds are prepared in industry, or how the NaCl in table salt formed naturally. (And even when burning sodium in chlorine, neither of the reactants are atomic, so even here there is no simple transfer of electrons between atoms.)

A new study reports a creative approach to modelling the atom motivated by a love story

Modelling 'the' atom

The story

Prologue

Chapter 1 – part 1

Chapter 1 – part 2

Chapter 2 and epilogue

Interpreting the narrative

Metaphorical meanings?

Orbitals and transitions

The rationale

A diagnostic assessment opportunity

A hybrid model?

An atom with seven energy levels?

Interorbital distances?

Spherical orbitals

Making sense of 486 nm and the 'THz 457s'

The Balmer series

A sleight of hand?

The model

Encouraging a new alternative conception?

To see through an orbital clearly?

Work cited:

Notes

It seems atoms are not quite as chemists imagine them not to be

A peer reviewed journal

A new theory of atomic structure

Orbital /energy shells

Definite positions of electrons

The problem addressed

Symmetrical atoms?

A flat model of the atom

But atoms are not all symmetrical?

Preventing negative electron pairs repelling each other

A new (mis)conception of ionic bonding

Finding space for the forces

Double bonds

Conclusion

Dr Menaa, Prof. Ibrahim, Prof. Yoon, Dr Parigger, Dr El-Behaedi…

Works cited:

Note:

Seeking the islets of Filipenka Henadzi

The orginal Mendeleev

The original Mendel

Calling out 'predatory' journals

Beyond Chadwick

Explaining a long-standing mystery

Masking true atomic number

Dubious physics

Naked protons

A new correspondence principle?

Confusing a teaching scheme for a mechanism?

The conservation of force conception (an alternative conception)

The revolution will not be televised…

Let down by poor journal standards

Works cited

Footnotes:

Ionic bonding – an often mislearnt topic

Ionic bonding – an often mistaught topic?

A curriculum model of ionic bonding

The teaching model

Does it matter if children are taught scientific fairy tales?

Sources cited: