Henry Gwyn Jeffreys Moseley

The English physicist Henry Gwyn Jeffreys Moseley, b. Nov. 23, 1887, d. Aug. 10, 1915, was the first to identify experimentally the nuclear charge of an element with what he called the atomic number, thus establishing the importance of the latter concept.

Using X-ray photographic techniques, Moseley obtained several quantitative relationships from which he predicted the existence of three missing elements--those with numbers 43, 61, and 75--in the periodic table, all of which were subsequently identified. Moseley was killed in action during World War I.

Robert Paul


Bibliography: Heilbron, J. L., H. G. J. Moseley: The Life and Letters of an English Physicist, 1887-1915 (1974); Jaffe, B., Moseley and the Numbering of the Elements (1971).

Last modified on: Monday, October 20, 1997.