SymbolTa
Latin nameTantalum
Atomic number73
Period6
Element categoryTransition elements
Relative atomic mass180.9479
GroupV.B
Electronegativity
1.5
Oxidation numbers
5
Electron configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d3 6s2
Density [g/cm3]
16.654
State
Solid
Melting point [°C]
2996
Boiling point [°C]
5660
Atomic radius [pm]
200
Covalent radius [pm]
138
Thermal conductivity [W m-1K-1]
57.5
Heat capacity [J K-1g-1]
0.14
Discovery
1802
Hardness [Mohs scale]
6.5
Vickers hardness [MPa]
873
Brinell hardness [MPa]
800
Young's modulus [GPa]
186
Electrical conductivity [S m-1]
8.1 · 106
Shear modulus [GPa]
69
1.st ionization energy [eV]
7.89
Stable isotopes
2
Unstable isotopes
18