Ytterbium vs Berkelium

PropertyYb YtterbiumBk Berkelium
Atomic number7097
SymbolYbBk
NameYtterbiumBerkelium
Categorylanthanideactinide
Standard Atomic Weight173.054 u247 u
Period67
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Xe]6s24f14[Rn]7s25f9
Oxidation states[0, 1, 2, 3][2, 3, 4, 5]
Electronegativity (Pauling)N/A1.3
Electron affinity-0.02 eV-0.5 eV
Density6900 kg/m³1.400000e+4 kg/m³
Melting point818.85 °C1049.85 °C
Boiling point1195.85 °C-273.15 °C
Discovery year18781949