Praseodymium vs Americium

PropertyPr PraseodymiumAm Americium
Atomic number5995
SymbolPrAm
NamePraseodymiumAmericium
Categorylanthanideactinide
Standard Atomic Weight140.90766 u243 u
Period67
GroupN/AN/A
Blockss
Phase at STPsolidsolid
Electron configuration[Xe]6s24f3[Rn]7s25f7
Oxidation states[0, 1, 2, 3, 4, 5][2, 3, 4, 5, 6, 7]
Electronegativity (Pauling)1.131.3
Electron affinity0.962 eV0.1 eV
Density6770 kg/m³1.369000e+4 kg/m³
Melting point930.85 °C1175.85 °C
Boiling point3519.85 °C2010.85 °C
Discovery year18851944