Discovery of Argon

Argon was identified as a new chemical element in 1894 by the physicist Lord Rayleigh and the chemist William Ramsay, working together rather than in competition. Rayleigh had noticed that nitrogen gas isolated from air was consistently about half a percent denser than nitrogen prepared by chemical means, a small but reproducible discrepancy; Ramsay, told of the puzzle, joined the investigation, and the two isolated a new, chemically unreactive gas from air that accounted for the extra density, naming it argon. Unlike the Priestley/Scheele dispute over the discovery of oxygen a century earlier, credit for argon was never contested: Rayleigh and Ramsay published jointly, and were awarded separate Nobel Prizes for the same discovery in the same year, 1904, Rayleigh in Physics and Ramsay in Chemistry, one of the few times a single finding has produced two Nobel Prizes in different categories rather than one prize shared or disputed between claimants. Argon's discovery, and Ramsay's further identification of helium, neon, krypton and xenon over the following four years, revealed an entire family of unreactive elements the periodic table's existing columns had no place for.