4
Be
9.0122
Beryllium
Element 4 · 9.0122 u · s-block
alkaline earth
A lightweight, strong metal used in aerospace and X-ray windows. Toxic if inhaled as dust.
Phase (STP)
Solid
Melting Point
1287 °C
Boiling Point
2470 °C
Density
1.85 g/cm³
Electronegativity
1.57
Atomic Radius
105 pm
Ionization Energy
900 kJ/mol
Electron Affinity
0 kJ/mol
Discovered
1798 · Louis Nicolas Vauquelin
Electron Configuration
[He] 2s2
Electron Orbitals
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