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The INTERNET Database of Periodic Tables

There are thousands of periodic tables in web space, but this is the only comprehensive database of periodic tables & periodic system formulations. If you know of an interesting periodic table that is missing, please contact the database curator: Mark R. Leach Ph.D.

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Weaver & Foster's Laminar Chart of the Elements

Weaver EC & Foster LS 1960, Chemistry For Our Times. 3rd ed., McGraw-Hill, New York, p. 382

René Vernon writes:

An earlier version of this table appeared in JChemEd in 1949. The authors then wrote:

"It is apparently difficult to give a proper idea of electronic configuration in two dimensions without spreading out vertically or horizontally, and thereby sacrificing the order of atomic number, or compactness, or both. In three dimensions it is entirely feasible, but the first reaction is to discard three dimensions as too awkward. The laminar chart here proposed seems to the authors to possess the advantages of both the two dimensional and three dimensional charts and to have none of their disadvantages.

"A minor feature of the table, introduced for reasons of expediency, is the artificial break between the first and the second main shell. Use is made of this space to print the traditional group headings, I A, III A, IVB, etc., which are firmly entrenched in the literature, and still find active use as classifying labels. Other objects in making the artificial break were to minimize the resemblance between hydrogen and the alkali metals and to emphasize helium's character as an inert gas (completed 1s subshell), rather than, as might otherwise be supposed, a member of the alkaline earth family.


"By another modification, constructing the Periodic Chart in the form of contour laminae, it is possible to represent actual energy levels without the necessity of referring to auxiliary tables. This is done by proportioning the rises between each subshell to correspond to the Pauling energy diagram. Thus, although the subshells having the same principal quantum number will be on the same contour lamina, they will not be on the same planar level. The recognition of these contour laminae is facilitated by the use of a different color for each one. A table of this type will then be more physically correct than the previous laminar models, and it is a question as to which form has the most practical utility.

"We believe that the laminar periodic tables, in either the original or a modified form, will greatly facilitate systematic teaching of the properties of the chemical elements. Students indoctrinated with the new system cannot fail to obtain a clearer and more lasting conception of the fundamental principles of inorganic chemistry."

Note the 4f and 5f series have been split into dyads of seven apiece. This is consistent with Shchukarev (1974, p. 118) who wrote that the filling sequence among the 4f metals is periodic, with two periods. Thus, after the occurrence of a half-full 4f subshell at europium and gadolinium, the filling sequence repeats with the occurrence of a full subshell at ytterbium and lutetium (Rokhlin 2003, pp. 4–5). A similar, but weaker, periodicity (Wiberg 2001, pp. 1643–1645) is seen in the actinoids, with a half-full 5f subshell at americium and curium, and a full subshell at nobelium and lawrencium.

Note that Zn, Cd, Lu and Hg have no electron numbers above them since the underlying shells were filled at Cu, Cd, Yb, and Au respectively.

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What is the Periodic Table Showing? Periodicity

© Mark R. Leach Ph.D. 1999 –

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