Moseley, Henry Gwyn-Jeffreys, << MOHZ lee, HEHN ree gwihn JEHF rihz, >> (1887-1915), was a British physicist noted for his research on X rays and atomic structure. About 1913, he discovered a systematic relationship between X-ray spectra and the atomic number of the elements giving off the X rays. This discovery enabled him to determine the atomic number of elements and to arrange them in the proper places in the periodic table. Moseley found four atomic numbers with no known elements—43, 61, 72, and 75. The elements that correspond to these numbers—technetium, promethium, hafnium, and rhenium—were discovered later. See Element, Chemical .
Moseley was born on Nov. 23, 1887, in Weymouth, England. He attended Oxford University and did research there and at the University of Manchester. Moseley was killed on Aug. 10, 1915, in the Allied invasion of Gallipoli during World War I.
