Comparison of Selenium and Polonium

Attribute	Polonium ×	Selenium ×
Atomic mass (u)	208.98243	78.97
Standard state	Solid	Solid
Oxidation states	+2 +4	-2 +4 +6
Electron configuration	[Xe]6s²4f¹⁴5d¹⁰6p⁴	[Ar]4s²3d¹⁰4p⁴
Atomic radius (van der waals) (pm)	197	190
Electronegativity (pauling scale)	2	2.55
Electron affinity (eV)	1.9	2.021
Ionization energy (eV)	8.417	9.752
Boiling point (K)	1235	958
Melting point (K)	527	493.65
Density (g/cm³)	9.32	4.809
Atomic number	84	34
Group name	Metalloid	Nonmetal
Discovered (year)	1898	1817
Symbol	Po	Se