Quick answerBeryllium (Be) is an alkaline earth metal with atomic number 4 and an atomic mass of 9.0122 (2023), in group 2, period 2. It was discovered by Louis Nicolas Vauquelin in 1798. It is used for X-ray windows and aerospace components. Its electron configuration is [He] 2s2.
Beryllium is a feather-light, steel-stiff metal used in X-ray windows, aerospace parts, and the mirrors of the James Webb Space Telescope.
Key facts
| Symbol | Be |
|---|---|
| Atomic number | 4 |
| Atomic mass | 9.0122 (IUPAC standard atomic weight, 2023) |
| Category | alkaline earth metal |
| Group | 2 |
| Period | 2 |
| Block | s-block |
| Electron configuration | [He] 2s2 |
| Discovered | Louis Nicolas Vauquelin, 1798 |
| Uses | X-ray windows, aerospace components, James Webb Space Telescope mirrors, nuclear reactors, precision instruments |
Quick quiz
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Keep exploring
- Periodic table — all 118 elements
- Magnesium (Mg) — another alkaline earth metal, atomic number 12
- Calcium (Ca) — another alkaline earth metal, atomic number 20
- Strontium (Sr) — another alkaline earth metal, atomic number 38
- Barium (Ba) — another alkaline earth metal, atomic number 56
- Radium (Ra) — another alkaline earth metal, atomic number 88
Sources & last updated
- CIAAW — Standard Atomic Weights
- PubChem Periodic Table
- Wikipedia — Timeline of chemical element discoveries
Last updated: . Figures are shown with their year; where sources disagree, the value is left out rather than estimated.