Atomic Element Z = 4 • Alkaline Earth Metal
Beryllium (Be) — Atomic Data, Electron Shells & Reactions
Beryllium (symbol Be, atomic number 4) has a standard atomic weight of 9.0122 u and ground-state configuration [He] 2s2.
Atomic Number (Z)
4
IUPAC Symbol
Be
Standard Atomic Weight
9.0122 g/mol
Period / Group / Block
2 / 2 / s-block
Condensed Electron Config
[He] 2s2
Full Subshell Config
1s2 2s2
Principal Shell Occupancy
[2, 2]
Pauling Electronegativity
1.57
First Ionization Energy
899 kJ/mol
Covalent Radius
96 pm
Melting Point
1560 K (1286.85 °C)
Boiling Point
2742 K (2468.85 °C)
Density
1.85 g/cm³
Oxidation States
+2
Be (Z=4) — Valence shell highlighted in vermilion