Henry Moseley (1887-1915) made many important contributions to science, including demonstrating that atomic numbers were not arbitrary but had a physical basis that could be measured. This breakthrough (Moseley's Law) would enable the elements in the periodic table to be put in their correct order and the existence of as-yet-unknown elements to be accurately predicted. His work ... provided one of the first experimental tests of quantum theory. Many believe that, had he lived, Moseley would have been awarded the Nobel Prize.