Comparison of Chlorine and Iodine

Attribute	Iodine ×	Chlorine ×
Atomic mass (u)	126.9045	35.45
Standard state	Solid	Gas
Oxidation states	-1 +1 +5 +7	-1 +1 +5 +7
Electron configuration	[Kr]5s²4d¹⁰5p⁵	[Ne]3s²3p⁵
Atomic radius (van der waals) (pm)	198	175
Electronegativity (pauling scale)	2.66	3.16
Electron affinity (eV)	3.059	3.617
Ionization energy (eV)	10.451	12.968
Boiling point (K)	457.55	239.11
Melting point (K)	386.85	171.65
Density (g/cm³)	4.93	0.003214
Atomic number	53	17
Group name	Halogen	Halogen
Discovered (year)	1811	1774
Symbol	I	Cl