4BeBeryllium9.01218315[He] 2s²
alkaline earth metal
Beryllium
Beryllium is a chemical element with symbol Be and atomic number 4. It is created through stellar nucleosynthesis and is a relatively rare element in the universe. It is a divalent element which occurs naturally only in combination with other elements in minerals.
A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.
Electrons by shell
Electron configuration
2s2
At a glance
- Atomic number
- 4
- Atomic mass
- 9.012183 u
- Phase
- Solid
- Density
- 1.85 g/cm³
- Melting point
- 1,560 K
- Boiling point
- 2,742 K
- First ionization energy
- 899.5 kJ/mol
- Electronegativity
- 1.57
- Electron affinity
- -48 kJ/mol
- Molar heat capacity
- 16.443 J/(mol·K)
- Period
- 2
- Appearance
- white-gray metallic
Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.
Keep exploring
Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.