Comparison of Chlorine and Bromine

Attribute	Bromine ×	Chlorine ×
Atomic mass (u)	79.9	35.45
Standard state	Liquid	Gas
Oxidation states	-1 +1 +5	-1 +1 +5 +7
Electron configuration	[Ar]4s²3d¹⁰4p⁵	[Ne]3s²3p⁵
Atomic radius (van der waals) (pm)	183	175
Electronegativity (pauling scale)	2.96	3.16
Electron affinity (eV)	3.365	3.617
Ionization energy (eV)	11.814	12.968
Boiling point (K)	331.95	239.11
Melting point (K)	265.95	171.65
Density (g/cm³)	3.11	0.003214
Atomic number	35	17
Group name	Halogen	Halogen
Discovered (year)	1826	1774
Symbol	Br	Cl