The chemical nature of element 72, subsequently named hafnium, is generally regarded as a prediction from Bohr's theory of the periodic system and hence as a prediction from quantum theory. It is argued that both of these views and in particular the latter are mistaken. The claim in favour of Bohr's theory is weakened by his accommodation of independent chemical arguments and the claim in favour of quantum theory is untenable since the prediction is not strictly deductive.

This article is a translation into english of a lecture given by paneth in 1931. The content of the work is described by the section titles: (1) the need for epistemological clarification of the fundamental concepts of chemistry, (2) the concept of substance in chemistry, (3) the epistemological standpoint of the ancient atomists, (4) the epistemological position of the concept of element introduced by lavoisier, (5) the double meaning of the chemical concept of element: 'basic substance' and 'simple substance', And (...) (6) the double meaning of other chemical concepts. Sections (4)-(6) are published in the following number of this journal. (staff). (shrink)

SummaryThe convening of the first three Solvay Chemistry Conferences in Brussels from 1922–1928 marked an important turning point for the discipline of chemistry. Whereas much of nineteenth-century chemical endeavour had focused on compositional and functional analysis of chemical compounds, many leaders in chemistry were turning to questions of molecular dynamics by the early twentieth century. Two competing schools of chemical dynamics, which were represented at the Solvay Conferences, were a predominantly English group (Lowry, Lapworth, Robinson, Ingold) who worked out electron (...) and ionic interpretations of organic reaction mechanisms, and a French group (Perrin, Job) who developed a generalized radiation hypothesis of reaction activation. While differences in conceptual and stylistic approach separated the two schools, they agreed on the need to apply contemporary physical theory to old chemical problems, and to develop a theoretical chemistry complementary to theoretical physics. (shrink)

The article discusses some of Heinz Post's views on correspondence and whether revolutions occur in science a la Kuhn. For example Post points out that the periodic table of the chemical elements has withstood any revolutions. Specific issues examined include the Paneth-Fajans controversy, the extent to which quantum mechanics provides an explanation for the periodic table and ab initio calculations in quantum chemistry.