Americium vs Curium

Side-by-side comparison of Americium (Am, element 95) and Curium (Cm, element 96) by atomic structure and physical properties.

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PropertyAm Americium Cm Curium
Atomic number9596
SymbolAmCm
NameAmericiumCurium
Categoryactinideactinide
Standard Atomic Weight243 u247 u
Period77
GroupN/AN/A
Blockff
Phase at STPSolidSolid
Electron configuration[Rn]5f77s2[Rn]5f76d17s2
Oxidation states[2, 3, 4, 5, 6, 7][3, 4, 5, 6]
Electronegativity (Pauling)1.31.3
Electron affinity0.1 eV0.277 eV
Density1.2e+4 kg/m³1.351e+4 kg/m³
Melting point1175.85 °C1344.85 °C
Boiling point2010.85 °C3126.85 °C
Discovery year19441944

Key Differences

PropertyAm AmericiumCm Curium
Standard Atomic Weight243 u ↓ lower247 u ↑ higher
Density1.2e+4 kg/m³ ↓ lower1.351e+4 kg/m³ ↑ higher
Melting point1175.85 °C ↓ lower1344.85 °C ↑ higher
Boiling point2010.85 °C ↓ lower3126.85 °C ↑ higher
Electron affinity0.1 eV ↓ lower0.277 eV ↑ higher
Electron configuration[Rn]5f77s2 [Rn]5f76d17s2