Whose work first identified the noble gases as a new family of elements?

William Ramsay played the key role in establishing the noble gases as a distinct group. In 1894, he helped identify argon, and over the next few years he and colleagues isolated neon, krypton, and xenon from air. These gases were chemically unusual because they were extremely unreactive, which is why they fit so neatly into a separate group on the periodic table. Their discovery expanded the table and showed that it was still incomplete. Ramsay received the Nobel Prize in Chemistry in 1904.