The Periodic Table since Mendeleev

More than 700 versions of the periodic table were produced in the century after Mendeleev’s table, and these have been analysed by Edward Mazurs in his 'Graphic Representations of the Periodic System During 100 Years', Mazurs was concerned with the format of these tables and devised an elaborate classification of them which enabled him to give each a code as follows:

(a.) Short, 8-column tables = code I ; medium, 18 column tables = code II; long, 32-column tables = code III

(b.) Three dimensional tables with curved or helical arrangements = A; two-dimensional curves and spirals = B; two-dimensional matrix layout = C

Within these main groups of further divisions depended upon the relative positions of groups and other properties. Thus Mendeleev ‘s table (Ramsay’s prediction of undiscovered gaseous elements in 1894) is categorised as IC2-1 and the modern long form of the table (the modern periodic table) is IIIC3-4.

A simpler and neater subdivision, and one that serves to explain why the latter is the preferred form is as follows:

(a.) Continuous versus discontinuous listing of the elements
(b.) The number of groups in the table : 8,18 or 32
(c.) Two or three-dimensional representation


Continuous tables

Since the elements are to be ranked in sequence according to atomic number 1 to 109, the natural way of presenting these is as a continuous tape that can then be looped as a helix or spiral so as to bring together elements of similar electronic configuration that share common properties. Although three-dimensional arrangements are possible and can be represented on paper, they have not been popular, and this may also explain why Chancourtois’s table did not receive the recognition it deserved.

Quite exotic loops and curls can be produced, such as that designed by Romanoff in 1934, but three-dimensional periodic tables are of little practical use. Two-dimensional continuous tables first appeared only a year after Mendeleev ‘s, when H Baumhauer designed a spiral table beginning with hydrogen in the centre, and this format is still to be seen in ‘ornamental’ tables because of its visual appeal. The Festival of Britain version of 1951 unfortunately crowds together the more common elements at the centre while giving the less important f-block elements a disproportionate amount of space at the periphery. Sometimes this circular format is imposed on the table by virtue of the medium itself, as on the medal issued to commemorate the Centenary of Mendeleev ‘s table in 1969.

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