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

Jess Tauber wrote:

Super-massives

Actually stellar phenomena may be TOO energetic to create super-massive nuclei, which is why we never actually see them. We might rather want to 'sneak' neutrons into these elements via low energy table-top experiments, atom by atom so we don't blow ourselves up in the process, within metallic matrices where coulombic barriers are said to be overcome in unusual fashion, and compound nuclei formed. I'm still not convinced this is all real, and the unwillingness of these folks to share a conversation or two is troubling, but they HAVE been burned several times since the days of Pons and Fleischer. Do they deserve it? Time will tell. In the meantime perhaps the best place to look is in the cores of exploded metallic asteroids, where such processes might have occurred naturally. After all, who expected to discover ancient natural fission reactors from the days when the U235/U238 ratio was MUCH higher than it is today. Add good sized electric pulses and hydrogen and you're in business. Did any floating metal ever face these conditions in the early solar system? Jess Tauber

Fri Jul 22 12:56:28 UTC 2011

Eric Scerri wrote:

First Member Rule

Hi Philip._______Yes but Valery is claiming that this is a universal rule that applies to all 32 groups and has not given any arguments for it. He will presumably appeal to chemical behavior in order to do this while being prepared to ignore the obvious chemical similarity between He and the other noble gases.______. The first member rule is by no means generally accepted or clear. Henry Bent, its leading champion uses it to argue for He above Be while Bill Jensen who first discussed it in the literature uses it to argue against He above Be as I discuss in my book. _________________ I am not claiming that triads can determine the structure of the periodic system from first principles, just that they might be useful in making one small correction, namely the position of H. This is also far more acceptable on chemical grounds than placing He above Be !

Fri Jul 22 09:54:16 UTC 2011

Philip Stewart wrote:

Super-massives

I haven't dismissed the search for super-massive elements; I just said the place to search is in the crust of neutron stars. I don't see how we can pile on enough neutrons for stability under terrestrial condiditions.

Fri Jul 22 09:47:16 UTC 2011

Eric Scerri wrote:

Synthesis of elements beyond 118

An interesting article on elements beyond 118 can be found at______ http://www.labnews.co.uk/laboratory_article.php/6691/2/Pointless-additions%27_________. This is relevant to the present debate because Martin Channon for example interprets the Stowe table to mean that there cannot possibly be any elements beyond 120, while Philip Stewart frequently dismissed the search for super-heavy elements.

Fri Jul 22 09:33:52 UTC 2011

Philip Stewart wrote:

Oddness of H and He

Triads are a consequence of the structure of the system, and a consequence cannot determine a structure. The difference between H and either Li or F is very marked; by its strong preference for covalent bonding it resembles C more than any other element. Not quite as peculiar as He. The oddness arises surely because in the K shell there cannot be an octet of 2 s and 6 p electrons.

Fri Jul 22 09:33:28 UTC 2011

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