Promethium vs Ytterbium

PropertyPm PromethiumYb Ytterbium
Atomic number6170
SymbolPmYb
NamePromethiumYtterbium
Categorylanthanidelanthanide
Standard Atomic Weight145 u173.054 u
Period66
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Xe]6s24f5[Xe]6s24f14
Oxidation states[2, 3][0, 1, 2, 3]
Electronegativity (Pauling)N/AN/A
Electron affinity0.129 eV-0.02 eV
Density7260 kg/m³6900 kg/m³
Melting point1041.85 °C818.85 °C
Boiling point2999.85 °C1195.85 °C
Discovery year19021878