Argon was the first noble gas that was discovered by Sir Henry Cavendish through his work to identify an unknown compound in air. After identifying Oxygen, he proceeded to react Oxygen and Nitrogen in the air to form Nitrous oxides. After chemical treatment with Sodium hydroxide a small bubble of gas remained that Cavendish identified as an unreactive gas, at the time this was Argon. It was not until 1895 and the use of spectrum analysis that Lord Rayleigh and William Ramsey discovered the unique spectrum of Argon, named after the Greek ‘Argos’ meaning inactive. Argon has a wide variety of uses in the metal industry due to its inert behaviour. It is often used in welding and cutting of metals and also to produce protective layers on metals such as Titanium. Originally, the symbol for Argon was A until 1957 when IUPAC decided to change the symbol to A. Argon makes up 1% of the earths atmosphere but the vast majority of Argon comes from the radioactive decay of Potassium-40. It is located in Group 18 as a non metal gas which is odourless and colourless. It has a melting point of -189°c and a boiling point of -185°c.
Sir William Ramsey, Baron Rayleigh