The Noble Gases
Sir William Ramsay, KCB (1852-1916) from Glasgow was awarded the 1904 Nobel Prize in Chemistry for his discovery of the Noble Gases. The descriptor ‘noble’ references their characterisation as ‘dignified’ or ‘high-ranking’ in the sense that they are shielded by their complete outer electron shells from other elements, meaning that they are the only elements that rarely react chemically to form compounds.
The six naturally occurring noble gases are: argon, neon, xenon, helium, krypton and radon (a synthetic one called oganesson was also created in 2002 for experimental purposes). These six are monatomic, odourless, tasteless, colourless, non-flammable and are in the air, as Ramsay explained in his 1896 publication, ‘The Gases of the Atmosphere’ . The noble gases form the last column in the periodic table and are also known as ‘Group 18’. Xenon is the one which is least resistant to reacting.
Ramsay first discovered argon in close liaison with Lord Rayleigh in 1894, followed by his finding that helium had similar properties in 1895. By 1898 he had methodically and painstakingly found xenon, krypton and neon, assisted by Londoner Dr Morris Travers (1872-1961), and latterly using a machine for liquefying air invented by Cheshire-born Dr William Hampson (1854-1926). Finally, in 1910 Ramsay proved that radon was the sixth noble gas.
(Images LtoR: Sir William Ramsay / Public domain, composition of air by Engineer09 at Wikimedia Commons / CC BY-SA 3.0)