Henry Moseley (1887–1915)

Henry Gwyn Jeffreys Moseley (1887–1915), an English physicist, by means of X-ray spectroscopy, established that the chemical properties of the elements are periodic functions of their atomic numbers rather than their atomic weights , as proposed by Dmitrii Ivanovich Mendeleev. He was able to explain a number of “inversions” in the table and predict a number of “missing” elements. His death three weeks before his 28th birthday, by a Turkish sniper’s bullet in the disastrous Gallipoli invasion in the Dardanelles, “might well have been the most costly single death of the war to mankind generally.”