Beryllium

Alkaline earth metal · 9.012183 u · group 2, period 2

Beryllium · Be

Atomic number4

SymbolBe

CategoryAlkaline earth metal

Standard stateSolid

Group · Period · Block2 · 2 · s

Electron configuration[He]2s2

Atomic mass9.012183 u

Atomic radius153 pm

Protons / Neutrons / Electrons4 / 5 / 4

Shells (e⁻ per shell)2, 2

Electronegativity (Pauling)1.57

Ionization energy9.323 eV

Electron affinity—

Oxidation states+2

Melting point1.56e+3 K · 1.29e+3 °C

Boiling point2.74e+3 K · 2.47e+3 °C

Density1.85 g/cm³

Year discovered1798

CPK color

#C2FF00

State at room temp (25 °C)

solid

Position