Protactinium

Symbol | Pa
Latin name | Protaktinium
Atomic number | 91
Period | 7
Element category | Inner transition elements
Relative atomic mass | 231.0359
Group | V.B
Electronegativity | 1.5
Oxidation numbers | 4, 5
Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p6 5f2 6d1 7s2
Density [g/cm3] | 15.37
State | Solid
Melting point [°C] | 1550
Boiling point [°C] | 4225
Thermal conductivity [W m-1K-1] | 47
Discovery | 1917
1.st ionization energy [eV] | 5.89
Stable isotopes | 0
Unstable isotopes | 13