Beryllium (Be)
Alkaline earth metal
Beryllium is a steel-grey, surprisingly rigid lightweight metal. It is transparent to X-rays, holds its shape at extreme temperatures, and strengthens alloys used in aerospace — but its dust is highly toxic.
Position on the periodic table
Atomic properties
| Atomic number | 4 |
|---|---|
| Atomic mass | 9.0122 amu |
| Electron configuration | 1s2 2s2 |
| Noble gas shorthand | [He] 2s2 |
| Electrons per shell | 2, 2 |
| Valence electrons (outer shell) | 2 |
| Common oxidation states | +2 |
| Electronegativity (Pauling) | 1.57 |
| Covalent radius (approx.) | 96 pm |
| First ionization energy | 899.5 kJ/mol |
| Electron affinity | -48 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 1.85 g/cm³ |
| Melting point | 1286.8 °C (1560 K) |
| Boiling point | 2468.8 °C (2742 K) |
| Appearance | white-gray metallic |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of beryllium
Beryllium's ground-state electron configuration is 1s2 2s2, usually shortened to [He] 2s2. Its electrons occupy 2 shells (2, 2), placing it in period 2 of the s-block. The 2 outer-shell electrons drive its bonding behaviour. Explore it interactively in the electron configuration calculator.
Uses of beryllium
- X-ray tube windows
- Springs and connectors in electronics (beryllium-copper alloys)
- Aerospace and satellite structures
- Mirrors for space telescopes
Biological role: None — beryllium and its compounds are toxic.
Occurrence: Rare; obtained from the minerals beryl and bertrandite.
Common compounds of beryllium
BeO
Beryllium oxide
BeCl2
Beryllium chloride
History and discovery
Discovered: 1798 — Louis Nicolas Vauquelin. Name origin: From beryl, the gemstone mineral in which it was discovered.
Louis-Nicolas Vauquelin identified beryllium in 1798 in beryl; Friedrich Wöhler and Antoine Bussy isolated the metal in 1828.
Safety notes
Inhaling beryllium dust can cause serious lung disease. It is handled only with professional protective equipment.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Beryllium
1. What is the chemical symbol of Beryllium?
2. What is the atomic number of Beryllium?
3. Which category does Beryllium belong to?
4. What is the state of Beryllium at room temperature?
5. Which period of the periodic table is Beryllium in?
Beryllium FAQs
What is the atomic number of beryllium?
Beryllium's atomic number is 4 — every beryllium atom has 4 protons in its nucleus.
What is the symbol for beryllium?
Be. From beryl, the gemstone mineral in which it was discovered.
Is beryllium a metal, nonmetal, or metalloid?
Beryllium is classified as a alkaline earth metal.
What state is beryllium at room temperature?
At about 25 °C, beryllium is a solid. It melts at 1286.8 °C.
How many valence electrons does beryllium have?
Beryllium has 2 electrons in its outer shell (shell pattern: 2, 2).
What is beryllium used for?
Key uses include: x-ray tube windows; springs and connectors in electronics (beryllium-copper alloys); aerospace and satellite structures.
Related elements
Keep working with this element
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