Comparison of Chlorine and Argon

Attribute	Chlorine ×	Argon ×
Atomic mass (u)	35.45	39.9
Standard state	Gas	Gas
Oxidation states	-1 +1 +5 +7	0
Electron configuration	[Ne]3s²3p⁵	[Ne]3s²3p⁶
Atomic radius (van der waals) (pm)	175	188
Electronegativity (pauling scale)	3.16	-
Electron affinity (eV)	3.617	-
Ionization energy (eV)	12.968	15.76
Boiling point (K)	239.11	87.3
Melting point (K)	171.65	83.8
Density (g/cm³)	0.003214	0.0017837
Atomic number	17	18
Group name	Halogen	Noble gas
Symbol	Cl	Ar
Discovered (year)	1774	1894