At Last, A Definitive Periodic Table?

  • DOI: 10.1002/chemv.201000107
  • Author: David Bradley
  • Published Date: 20 July 2011
  • Source / Publisher: ChemistryViews.org
  • Copyright: WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
thumbnail image: At Last, A Definitive Periodic Table?

Discussion Spawned Development in the Field

A recent Research Highlight on ChemistryViews.org on the nature of the Periodic Table of the Elements attracted a lot of readers and has stimulated an ongoing debate among those arguing as to whether or not there is a definitive format for this iconic tool. Intriguingly, however, the article and ensuing discussion has also spawned a development in this field courtesy of UCLA chemistry professor Eric Scerri.


"One of the most positive outcomes of the very popular 'Periodic Debate' discussion has been that the relative virtues of the so-called 'Stowe' and the 'left-step' periodic table, in various formats, have been vigorously discussed," Scerri says. "In the course of this debate I have come up with a compromise table which includes the best features of both types of systems."

Stowe Table

The Stowe table is named for Tim Stowe who published his system on a website several years ago but has, apparently, published nothing since. Chemists have attempted to track him down, but he seems to have vanished from the community without a trace, leaving behind an interesting periodic legacy. "Many people interested in the periodic table have tried to track him down," says Scerri, "but nobody has yet succeeded."


Stowe’s system is four dimensional in the following sense: the x and y axes depict values of the m and s quantum numbers. In the case of the s or spin quantum number values are either positive or negative, while the values of the m quantum number can range from -l, through 0 up to +l in integer steps. The z-axis is taken as the n or main quantum number representing the main shell. The fourth dimension, which obviously cannot be depicted spatially, is shown by the use of different colors each of which denotes a different value of the l quantum number. In this way, the Stowe table seeks to depict the four quantum numbers of the electron that differentiates each atom from the previous one in the sequence of increasing atomic numbers.


However, the Stowe representation has several drawbacks, which is where Scerri's new approach comes to the fore. The left-step table has received a great deal of attention in recent years. It was originally designed by the French engineer and polymath Charles Janet in the 1920s. However, with the advent of quantum mechanics and the quantum mechanical account of the periodic system it was realized that his system displays the elements in order of increasing n + l values of the differentiating electron. Many authors have claimed that this is a more natural system since electron filling accords with this criterion rather than increasing values of n.

New Modifications by Scerri

Scerri has now modified the left-step table by combining it with Stowe’s idea of using the quantum numbers explicitly to represent the elements in the periodic system. "The notion that n + l is more fundamental than n alone is key," says Scerri. "The format I have now constructed depicts the arrangement of the elements in this fashion for elements 1 to 65 inclusive and can be easily extended up to 118 the currently heaviest atom and indeed beyond to elements that will in all probability be
synthesized soon." In what he now calls the Stowe-Janet-Scerri periodic system each level represents a particular value of n + l which take the form of horizontal periods in the case of the original Janet table.


Following Scerri's introduction of this new layout in the comments of the ChemistryViews item, commenter Valery Tsimmerman, pointed out that Scerri's efforts in re-working the Stowe table is bringing us closer to the realization of the numerical and geometrical regularities of the Periodic System. Tsimmerman also claims to have devised the perfect Periodic Table based on the concept of tetrahedral sphere packing.

Tsimmerman's Concept of Tetrahedral Sphere Packing

Tsimmerman points out that chemists such as Henry Bent mentioned that every other alkaline earth atomic number equals to four times the pyramidal number, while Wolfgang Pauli noticed that length of periods are double square numbers: 2x(1, 4, 9, 16). This latter point is, Tsimmerman says, not surprising because square numbers are the sums of odd numbers 1, 1+3, 1+3+5, 1+3+5+7 ... We know the meaning of odd numbers in the periodic system. They are the lengths of s, p, d and f blocks. Adding the number of elements in block rows results in the lengths of the periods. Adding square numbers results in pyramidal numbers: 1, 1+4=5, 1+4+9=14, 1+4+9+16=30. Multiply them by four and you will get every other tetrahedral number 4, 20, 56, 120 ... Those are the atomic numbers of Be, Ca, Ba and Ubn. "Great scientists like Pauli, Niels Bohr and others were marveling at numerical relationships found in periodic system," says Tsimmerman. He suggests that Scerri's latest periodic table is not quite the final version and suggests that any further reworking of Stowe's table will take us closer to a definitive 3D table.


"I hope that this system will not be just another periodic table to add to the depository of tables that people dream up every so often but may represent a definitive step forward in the quest for improved periodic tables," Scerri told us.


  • Periodic Debate, David Bradley
    Mendeleev's Periodic Table is, for many, the symbol of chemistry but is the current layout the best one?
    including discussion mentioned in article

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5 Comments

Eric Scerri wrote:

To Philip and Jess

I have published two forms of the H in the halogens table. The one you mention and another one which has a more pleasing shape and does not show pseudo lateral symmetry. The paper appeared in the Journal of Chemical Education and I am sending you a copy via E-mail now. You have commented on it before and said that it was a form that Janet himself toyed with for a while. If shape matters so much, which it does not to me, then I give you that version of the H in the halogens table. Something you said about gaps, is resonating with me recently. It occurs to me that there is one similarity between my H in the halogens (both formats) and Janet's LST and also Janet-Stowe-Scerri as compared with the traditional medium-long form. It is that all these alternative forms place H right next to He. Can we discuss whether this is an advantage or not perhaps since none of the usual partisanship should intrude? To what extent does the placement of H and He as widely separated in the medium-long form table represent a mistake or misrepresentation? Jess I think you are asking the wrong people.

Sat Jul 23 13:02:05 UTC 2011

Jess Tauber wrote:

Things to discuss

Well, I wish someone would answer my prior question about what counts as sphericality in nuclei. At least THAT should be relatively definitive . Jess Tauber

Sat Jul 23 12:29:17 UTC 2011

Philip Stewart wrote:

Conflict

Eric, if your other conflicting proposal is the one with H and the halogens on the left, and the O group on the right, I'm afraid for me it is a non-starter. It has a pretty symmetry, at the cost of putting the f block as an appendix, but it would be unhelpful and indeed confusing for people learning chemistry. It mixes shells and has gaps and breaks where none is justified. Nor do I see "Janet-Stowe-Scerri" as an advance on Janet or Adomah. I agree with Valery, there is nothing to discuss.

Sat Jul 23 08:44:38 UTC 2011

Jess Tauber wrote:

Varia

I know that Valery has Henry's phone number, I have it somewhere as well. As for properties of chemicals it is interesting that even supposed dimensionless constants seem to vary in the universe of space and time- the fine structure constant changes in astronomical measurements depending on what direction one is looking at. And radioactive decay rates vary depending on whether the sun is flaring or how close the earth is to it, indicating effect of neutrino flux on nuclear stabilities. Things are FAR more interesting than we thought. Perhaps the particular chemical behaviors we unendingly argue about are just the local balance. Jess Tauber

Sat Jul 23 02:36:28 UTC 2011

Eric Scerri wrote:

echoes of Henry Bent?

Philip let me explain again. I now have two conflicting proposals out there and I am not particularly "stuck" on either of them. One has He in the noble gases (Z-triads based) and the newer one has He in the alkaline earths (Janet-Stowe-Scerri system). So far I see no compelling argument for supporting one or the other more strongly, despite the title of this website, and I am using this forum in the hope of subjecting both proposals to as much criticism as possible. Is that OK or do I have to play the game of rigidly "sticking" to one proposal? Incidentally, has anyone heard from Henry Bent recently?

Sat Jul 23 01:46:48 UTC 2011

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