ASCII PERIODIC TABLE OF THE ELEMENTS
Ar
Relative atomic mass: 39.948 ± 0.001
English: Argon
French: Argon
Croatian: Argon
German: Argon
Italian: Argo
Spanish: Argón
Atomic number: 18
Group numbers: 18
Period: 3
Standard state (20 °C): gas
Discovery: 1894 Lord Raleigh, Sir William Ramsay (GB)
Argon was discovered by Lord Raleigh and Sir William Ramsay (GB) in 1894. The origin of the name comes from the Greek word 'argos' meaning 'inactive'. It is a colourless and odourless noble gas, chemically inert. Argon is the third most abundant element in the earth's atmosphere and makes up about 1%. Argon is continuously released into the air by decay of radioactive potassium-40. Pure form is obtained from fractional distillation of liquid air. It is used in lighting products, and is often used in filling incandescent light bulbs. Some is mixed with krypton in fluorescent lamps. Crystals in the semiconductor industry are grown in argon atmospheres.
Electronic configuration: [Ne] 3s2 3p6
Formal oxidation number: 0
Atomic radius: 188 pm
Electronegativities: -
Thermal conductivity: 0.0179 W/(m K)
Electrical resistivity (20 °C): - μΩcm
Melting point: -189.34 °C
Boiling point: -185.89 °C
Heat of fusion: 1.21 kJ/mol
Heat of vaporization: 6.53 kJ/mol
Heat of atomization: 0 kJ/mol
17Cl <= 18Ar => 19K
ASCII Periodic Table of the Elements
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31 Mar. 2008
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