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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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1958

Landau & Lifshitz's Periodic System of Mendeleev

L.D. Landau & E.M. Lifshitz, Quantum Mechanics (Volume 3 of A Course of Theoretical Physics), pages 255-258. (Note: First published in English in 1958, the link is to the 1963 3rd ed. of the English version translated from Russian.)

René Vernon writes:

The authors discuss aspects of the periodic system of D I Mendeleev. The electron configurations of hydrogen & helium are briefly noted. This is followed by three tables setting out the electron configurations of the s, p, d & f elements.

Some extracts from the text follow:

"The elucidation of the nature of the periodic variation of properties, observed in the series of elements when they are placed in order of increasing atomic number, requires an examination of the peculiarities in the successive completion of the electron shells of atoms." (p. 252)

"Many properties of atoms (including the chemical properties of elements...) depend principally on the outer regions of the electron envelopes." (p. 254)

"The elements containing complete d and f shells (or not containing these shells at all) are called elements of the principal groups; those in which the filling up of these states is actually in progress are called elements of the intermediate groups. These groups of elements are conveniently considered separately." (p. 254)

"We see that the occupation of different states occurs very regularly in the series of elements of the principal groups: first the s states and then the p states are occupied for each principal quantum number n. The electron configurations of the ions of these elements are also regular (until electrons from the d and f shells are removed in the ionisation): each ion has the configuration corresponding to the preceding atom. Thus, the Mg+ ion has the configuration of the sodium atom, and the Mg++ ion that of neon." (p. 255)

"Let us now turn to the elements of the intermediate groups. The filling up of the 3d, 4d, and 5d shells takes place in groups of elements called respectively the iron group, the palladium group and the platinum group. Table 4 gives those electron configurations and terms of the atoms in these groups that are known from experimental spectroscopic data. As is seen from this table, the d shells are filled up with considerably less regularity than the s and p shells in the atoms of elements of the principal groups. Here a characteristic feature is the 'competition' between the s and d states."

"This lack of regularity is observed in the terms of ions also: the electron configurations of the ions do not usually agree with those of the preceding atoms. For instance, the V+ ion has the configuration 3d4 (and not 3d24s2 like titanium) ; the Fe+ ion has 3d64s1 (instead of 3d54s2 as in manganese)."

"A similar situation occurs in the filling up of the 4f shell; this takes place in the series of elements known as the rare earths. † The filling up of the 4f shell also occurs in a slightly irregular manner characterised by the 'competition' between 4f, 5d and 6s states."

"† In books on chemistry, lutetium is also usually placed with the rare-earth elements. This, however, is incorrect, since the 4f shell is complete in lutetium; it must therefore be placed in the platinum group."

"The last group of intermediate elements begins with actinium. In this group the 6d and 5f shells are filled, similarly to what happens in the group of rare-earth elements." (p. 256–257)

The authors exclude lanthanum from the rare earths since the 4f shell has not started filling. Yet actinium and thorium are included by them with what we now call the actinoids even though these two metals have no f electrons. No explanation is provided for this puzzling lack of consistency with their categories.





René Vernon writes: I have joined up their one note and three tables. (Curium was the last known element at their time of writing; transcurium elements are shown in parentheses.):

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