Beryllium (Be) is chemical element 4, an alkaline earth metal in group 2, period 2 (PubChem).
- Atomic number: 4
- Symbol: Be
- Group: 2
- Period: 2
- Atomic mass: 9.012183 u
- Electron configuration: [He]2s2
- Electronegativity (Pauling scale): 1.57
- Atomic radius (van der Waals): 153 pm
- Ionization energy: 9.323 eV
- Oxidation states: +2
- Standard state: Solid
- Melting point: 1560 K
- Boiling point: 2744 K
- Density: 1.85 g/cm³
- Chemical group: Alkaline earth metal
- Year discovered: 1798