Hafnium vs Mendelevium

PropertyHf HafniumMd Mendelevium
Atomic number72101
SymbolHfMd
NameHafniumMendelevium
Categorytransition-metalactinide
Standard Atomic Weight178.49 u258 u
Period67
Group4N/A
Blockss
Phase at STPsolidsolid
Electron configuration[Xe]6s24f145d2[Rn]7s25f13
Oxidation states[-2, 0, 1, 2, 3, 4][2, 3]
Electronegativity (Pauling)1.31.3
Electron affinity0.178 eV0.997 eV
Density1.330000e+4 kg/m³1.030000e+4 kg/m³
Melting point2232.85 °C826.85 °C
Boiling point4602.85 °C-273.15 °C
Discovery year19111955