Terbium vs Neptunium

PropertyTb TerbiumNp Neptunium
Atomic number6593
SymbolTbNp
NameTerbiumNeptunium
Categorylanthanideactinide
Standard Atomic Weight158.92535 u237 u
Period67
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Xe]6s24f9[Rn]7s25f46d1
Oxidation states[0, 1, 2, 3, 4][2, 3, 4, 5, 6, 7]
Electronegativity (Pauling)N/A1.36
Electron affinity1.124 eV0.48 eV
Density8230 kg/m³2.025000e+4 kg/m³
Melting point1355.85 °C643.85 °C
Boiling point3229.85 °C3901.85 °C
Discovery year18431940