Beryllium vs Boron

PropertyBe BerylliumB Boron
Atomic number45
SymbolBeB
NameBerylliumBoron
Categoryalkaline-earth-metalmetalloid
Standard Atomic Weight9.012183 u10.8135 u
Period22
Group213
Blocksp
Phase at STPsolidsolid
Electron configuration[He]2s2[He]2s22p1
Oxidation states[0, 1, 2][-5, -1, 0, 1, 2, 3]
Electronegativity (Pauling)1.572.04
Electron affinity-0.52 eV0.27972 eV
Density1850 kg/m³2370 kg/m³
Melting point1286.85 °C2074.85 °C
Boiling point2470.85 °C3999.85 °C
Discovery year17971808