Beryllium vs Mendelevium

PropertyBe BerylliumMd Mendelevium
Atomic number4101
SymbolBeMd
NameBerylliumMendelevium
Categoryalkaline-earth-metalactinide
Standard Atomic Weight9.012183 u258 u
Period27
Group2N/A
Blockss
Phase at STPsolidsolid
Electron configuration[He]2s2[Rn]7s25f13
Oxidation states[0, 1, 2][2, 3]
Electronegativity (Pauling)1.571.3
Electron affinity-0.52 eV0.997 eV
Density1850 kg/m³1.030000e+4 kg/m³
Melting point1286.85 °C826.85 °C
Boiling point2470.85 °C-273.15 °C
Discovery year17971955