4Be9.0122
Beryllium (Be)
Element 4 Ā· Alkaline earth metal
Beryllium (Be) is a chemical element with atomic number 4. It is classified as an alkaline earth metal in period 2, group 2 of the periodic table (the s-block). Its standard atomic weight is 9.0122 u and its ground-state electron configuration is [He] 2sĀ².
Beryllium facts
| Atomic number (Z) | 4 |
|---|---|
| Symbol | Be |
| Standard atomic weight | 9.0122 u |
| Category | Alkaline earth metal |
| Group | 2 |
| Period | 2 |
| Block | s-block |
| Electron configuration | [He] 2sĀ² |
| Electronegativity (Pauling) | 1.57 |
| State at 20 Ā°C | Solid |
| Protons / electrons | 4 / 4 |
| Neutrons (most common isotope, approx.) | 5 |
| Molar mass | 9.0122 g/mol |