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- Who was John David Main Smith? | OUPblog
Who was John David Main Smith? Essays in the Philosophy of Chemistry By Eric Scerri March 12th This blog post concerns a virtually unknown chemist, John David Main Smith, who contributed a significant piece of research in atomic physics in the early s at the time when knowledge of the field was undergoing very rapid changes. Main Single essential idea is so little known that I had to search far and wide for a photograph of him before finally obtaining one from his son who is still living in the south of England.
As a result, the papers did not have any serious influence on chemists and certainly not on physicists, with a few minor exceptions. What Main Smith did was to take on the views of the mighty physicist, Niels Bohr, by proposing some improved electronic arrangements for the atoms of many elements.
These new arrangements were independently, rediscovered by an almost equally obscure English theoretical physicist, Edmund Single essential idea, who at the time was a graduate student at the University of Cambridge.
For example, in the case of single essential idea second shell, which had long been known to contain eight electrons, Bohr regarded the electronic structure to consist of two sub-shells each containing four electrons.
Main Smith had the temerity to challenge this view and to claim that the second shell should be regarded as having a grouping of 2,2 and 4 electrons instead on the basis of detailed chemical evidence.
Similarly Main Smith held that every shell begins with a sub-shell containing just two electrons. In contemporary terms he could be said to have discovered the existence of s-orbitals, and the fact that each shell begins with such an s-orbital.
On the other hand, here is one instance in which Main Smith turned out to be rather mistaken. Unfortunately this view stands in complete opposition to the currently accepted wisdom whereby there is indeed an analogous long period of 32 elements and starting with actinium at which point we do see a series of elements that are analogous to the rare earth elements.
This modern view is generally attributed to the American chemist Glen Seaborg who proposed his amendment to the periodic table in the s.
In fact the idea was first proposed by Charles Janet, another lesser-known scientist who unambiguously anticipated this idea in the early s. Another concept that can definitely be dating helmstedt to Main Smith was later named the inert pair effect by the chemistry Neville Sidgwick.
The idea of wisdom will be present on every stage of these considerations. However, in order to achieve a synthesis, one has to start with the analysis. It is stated that every great philosopher has had only one essential idea which they later developed in a system. It is already sketched in his earliest work, where he tries to solve aporetic difficulties resulting from the Cartesian, Kantian and Fichtean subjectivist-idealistic approach.
The essential idea is that as one descends several groups in the p-block of the periodic table there is an increasing tendency for two of the outermost electrons to not be involved in covalent bonding. For example the lower elements tin and lead situated in group 14 of the periodic table form di-chlorides whereas the higher members of the group such as carbon and silicon invariably form tetra-chlorides.
The original explanation of the inert pair effect, suggested by Single essential idea, was that the valence electrons in an s-orbital are more tightly bound and are künstler partnervermittlung lower energy than electrons in p orbitals and therefore less likely to be involved in bonding.
Разреши-ка мне им заняться, - спокойно сказал Хилвар. - Я привык общаться с животными.
However this explanation was subsequently found wanting. More recently, some of these anomalies have been explained as resulting from relativistic effects.
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To conclude, Main Smith might be regarded as one of the missing links in the history of twentieth century atomic science. Featured image credit: Niels Bohr in Public Domain via Wikimedia Commons.
Eric Scerri is a chemist, writer, and philosopher of science who teaches at the University of California, Los Angeles. Posted In:.