Boron

Symbol | B
Latin name | Borum
Atomic number | 5
Period | 2
Element category | Metalloids
Relative atomic mass | 10.811
Group | III.A
Electronegativity | 2.0
Oxidation numbers | 3
Electron configuration | 1s2 2s2 2p1
Density [g/cm3] | 2.34
State | Solid
Melting point [°C] | 2300
Boiling point [°C] | 2550
Atomic radius [pm] | 87
Covalent radius [pm] | 82
Thermal conductivity [W m-1K-1] | 27
Heat capacity [J K-1g-1] | 1.026
Discovery | 1808
Hardness [Mohs scale] | 9.3
Vickers hardness [MPa] | 4.9 · 104
Electrical conductivity [S m-1] | 5 · 10-6
1.st ionization energy [eV] | 8.298
2.nd ionization energy [eV] | 25.154
3.rd ionization energy [eV] | 37.93
Stable isotopes | 2
Unstable isotopes | 4