Comparison of Tantalum and Rhenium

Attribute	Rhenium ×	Tantalum ×
Atomic mass (u)	186.207	180.9479
Standard state	Solid	Solid
Oxidation states	+4 +6 +7	+5
Electron configuration	[Xe]6s²4f¹⁴5d⁵	[Xe]6s²4f¹⁴5d³
Atomic radius (van der waals) (pm)	217	217
Electronegativity (pauling scale)	1.9	1.5
Electron affinity (eV)	0.15	0.322
Ionization energy (eV)	7.88	7.89
Boiling point (K)	5869	5731
Melting point (K)	3459	3290
Density (g/cm³)	20.8	16.4
Atomic number	75	73
Group name	Transition metal	Transition metal
Discovered (year)	1925	1802
Symbol	Re	Ta