Ytterbium vs Actinium

PropertyYb YtterbiumAc Actinium
Atomic number7089
SymbolYbAc
NameYtterbiumActinium
Categorylanthanideactinide
Standard Atomic Weight173.054 u227 u
Period67
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Xe]6s24f14[Rn]7s26d1
Oxidation states[0, 1, 2, 3][3]
Electronegativity (Pauling)N/A1.1
Electron affinity-0.02 eV0.35 eV
Density6900 kg/m³1.007000e+4 kg/m³
Melting point818.85 °C1050.85 °C
Boiling point1195.85 °C3197.85 °C
Discovery year18781899