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Moseley, Henry Gwyn Jeffreys

ray atomic element metals

[mohz lee] (1887–1915) British experimental physicist: showed identity of atomic number and nuclear charge of a chemical element.

Moseley came from a family of scientists and graduated from Oxford in physics in 1910. At once he joined in Manchester, but in 1913 he returned to Oxford to work. In 1914 he visited Australia, and on the outbreak of the First World War he joined the Royal Engineers and later fought at Gallipoli. He was shot through the head by a Turkish sniper there during the battle of Suvla Bay.

Moseley’s major work was on the characteristic X-rays which and others had shown to be produced from metals used as targets in an X-ray tube work had shown that X-ray frequencies could be measured by crystal diffraction, and Moseley was instructed in this by . In 1913, using a crystal of potassium hexacyanoferrate(II) to measure the X-rays, he used over 30 metals (from Al to Au) as targets, and found that the X-ray lines changed regularly in position from element to element, in the order of their position in the periodic table. He suggested that this regular change must mean that the nuclear charge can be equated with what he called ‘the atomic number’. His work allowed prediction that six elements were missing from the table and, from their position, their properties and likely association could be predicted. As a result, these new elements were soon sought and found. The relation between an element’s X-ray frequency and its atomic number is known as Moseley’s Law. He was also able to resolve confusion over the identity of the rare earth metals, but his major achievement was to link chemical behaviour (as shown by an element’s place in the periodic table) with the physics of atomic constitution. Rutherford called him ‘a born experimenter’ who, as described it, ‘called the roll of the elements’.

Moses [next] [back] Morton, Peter - Overview, Personal Life, Career Details, Social and Economic Impact, Chronology: Peter Morton

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