INORGANIC CHEMISTRY A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site argon (Ar) Argon. Credit: Pslawinski & Wikipedia A colorless, odorless, highly unreactive gaseous element, which is the third most abundant gas in Earth's atmosphere (making up approximately 1 percent of the atmosphere). It is obtained commercially by fractionation of liquid air. Argon is one of the inert gases. It is used in electric lights, fluorescent tubes, electronic valves, and as an inert-gas shield in arc-welding. The discovery of argon was announced Lord Rayleigh and William Ramsay at Oxford in 1894. Its name comes from the Greek argos, meaning "inactive". atomic number 18 relative atomic mass 39.948 electron configuration 1s22s22p63s23p6 first ionization energy 1521 kJ/mol atomic radius 95 pm melting point -189.4 °C (-308.9 °F) boiling point -185.9 °C (-302.6 °F) relative density 1.848 Related category    • INORGANIC CHEMISTRY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP