NO. 004Alkaline Earth

Be

Beryllium

Beryllium is a hard, gray metal known for its stiffness and light weight.

Crystal Structure

Hexagonal close-packed (hcp)

Atomic Mass9.0122 u

Density1.85 g/cm³

Melting Point1560 K

Boiling Point2742 K

Atomic Radius112 pm

Electronegativity1.57

Ionization Energy900 kJ/mol

Electron Affinity0 kJ/mol

Bonding TypeMetallic

Oxidation States2

Acid/BaseBasic

ReactivityMedium

Electron Configuration

[He] 2s2

Discovered ByLouis Nicolas Vauquelin

Year1798

Known Isotopes

Beryllium-9