Chromium vs Protactinium

PropertyCr ChromiumPa Protactinium
Atomic number2491
SymbolCrPa
NameChromiumProtactinium
Categorytransition-metalactinide
Standard Atomic Weight51.9961 u231.03588 u
Period47
Group6N/A
Blockss
Phase at STPsolidsolid
Electron configuration[Ar]3d54s1[Rn]7s25f26d1
Oxidation states[-4, -2, -1, 0, 1, 2, 3, 4, 5, 6][2, 3, 4, 5]
Electronegativity (Pauling)1.661.5
Electron affinity0.675 eV0.123 eV
Density7150 kg/m³1.537000e+4 kg/m³
Melting point1906.85 °C1571.85 °C
Boiling point2670.85 °C-273.15 °C
Discovery year17971913