Curium vs Meitnerium

PropertyCm CuriumMt Meitnerium
Atomic number96109
SymbolCmMt
NameCuriumMeitnerium
Categoryactinidetransition-metal
Standard Atomic Weight247 u278 u
Period77
GroupN/A9
Blockss
Phase at STPsolidN/A
Electron configuration[Rn]7s25f76d1[Rn]7s25f146d7(calculated)
Oxidation states[3, 4, 5, 6][1, 3, 4, 6, 8, 9]
Electronegativity (Pauling)1.3N/A
Electron affinity0.277 eV1.7 eV
Density1.351000e+4 kg/m³3.740000e+4 kg/m³
Melting point1344.85 °C-273.15 °C
Boiling point3126.85 °C-273.15 °C
Discovery year19441982