The periodic classification and the problem of chemical evolution / by George Rudorf.

  • Rudorf, George.
Date:
1900
Catalogue details

Licence: In copyright

Credit: The periodic classification and the problem of chemical evolution / by George Rudorf. Source: Wellcome Collection.

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    0 F, Cl, Br, I S, Se, Te P, As, Sb C, B, Si Ti, Ta, W Mo, V, Cr Bi, Pb, Ag, Hg, Cu Os, Ir, Rh, Pt, Pd, Au N H Li, Na, K Mg, Ca, Sr, Ba G, Ce, La Zr, Th, A1 Sn, Cd, Zn Ur, Mu, Ni, Fe In another table a few more elements are included. Erbium, yttrium, terbium and didymium are added to the cerium group ; niobium and pelopium to the tantalum group ; cobalt and ruthenium to the iron and platinum groups respectively. It will be seen that oxygen, nitrogen and hydrogen are placed alone at the head of the table. This is due to their being supposed to be without analogues, which we know now not to be the case for oxygen and nitrogen. Again elements, which we do not group together, are found in the same set in the table, e.g., boron with carbon and silicon, beryllium (G) with the rare earths cerium, etc. Gmelin claims as a feature of his classification that the more electro- positive elements are on the right and the more electro-negative elements on the left of this table. Pettenkofer.—In 1850 Pettenkofer1 read a paper before the mathematical physics class of the Bavarian Academy of Sciences on “ The Regular Diffei’ences between the Equivalent Numbers of the so-called Simple Radicals.” The contents of this paper did not become generally known until 1858, when a reprint appeared in Liebig’s Annalen 'Ann. 105 (1858), p. 188.
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