#5 Boron

Boron is a non metallic element and the only non-metal of the group 13 of the periodic table the elements. Boron is electron-deficient, possessing a vacant p-orbital. It has several forms, the most common of which is amorphous boron, a dark powder, unreactive to oxygen, water, acids and alkalis.

Atomic mass:10.811 amu

Melting point:2300.0 C (2573.15 K, 4172.0 F)

Boiling point:2550.0 C (2823.15 K, 4622.0 F)

Density:293 K: 2.34 g/cm3