Chromium vs Promethium

PropertyCr ChromiumPm Promethium
Atomic number2461
SymbolCrPm
NameChromiumPromethium
Categorytransition-metallanthanide
Standard Atomic Weight51.9961 u145 u
Period46
Group6N/A
Blockss
Phase at STPsolidsolid
Electron configuration[Ar]3d54s1[Xe]6s24f5
Oxidation states[-4, -2, -1, 0, 1, 2, 3, 4, 5, 6][2, 3]
Electronegativity (Pauling)1.66N/A
Electron affinity0.675 eV0.129 eV
Density7150 kg/m³7260 kg/m³
Melting point1906.85 °C1041.85 °C
Boiling point2670.85 °C2999.85 °C
Discovery year17971902