General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles


Name Argon Symbol Ar
atomic number 18 Atomic weight 39.948
Density @ 293 K 0.0017824 g/cm3 Atomic volume 28.5 cm3/mol
Group Noble Gas discovered 1894


state (s, l, g) g
melting point 84 K boiling point 87.3 K
Heat of fusion 1.188 kJ/mol Heat of vaporization 6.447 kJ/mol
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1st ionization energy 1520.5 kJ/mole electronegativity
2nd ionization energy 2665.8 kJ/mole electron affinity kJ/mole
3rd ionization energy 3930.8 kJ/mole Specific heat 0.520 J/gK
heat atomization 0 kJ/mole atoms

Oxidation & Electrons

Shells 2,8,8 electron configuration [Ne] 3s2 3p6
minimum oxidation number 0 maximum oxidation number 0
min. common oxidation no. 0 max. common oxidation no. 0
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Appearance & Characteristics

structure fcc: face-centered cubic color colorless
uses lasers, light bulbs toxicity no
hardness mohs characteristics Inert


reaction with air none reaction with 6M HCl none
reaction with 6M HCl none reaction with 15M HNO3 none
reaction with 6M NaOH none
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Other Forms

number of isotopes 3 hydride(s) none
oxide(s) none chloride(s) none


ionic radius (2- ion) pm ionic radius (1- ion) pm
atomic radius 98 pm ionic radius (1+ ion) pm
ionic radius (2+ ion) pm ionic radius (3+ ion) pm
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thermal conductivity 0.02 J/m-sec-deg electrical conductivity 0 1/mohm-cm
polarizability 1.586 A^3


source Air rel. abund. solar system 5.004 log
abundance earth's crust 0.5 log cost, pure 0.5 $/100g
cost, bulk $/100g
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World Wide Web presentation of Chemicool Periodic Table is © Copyright 1996-99 by David D. Hsu. Some data were provided by and used with the permission of JCE Software and is owned and copyright by the Division of Chemical Education, Inc. Additional data were provided by Perkin-Elmer through Peter Lykos of IIT. The information may not be redistributed without the permission of David Hsu or JCE Software.