Be
Beryllium
Beryllium is a chemical element with the symbol Be and atomic number 4. It has a standard atomic weight of 9.0122, sits in period 2 and group 2, and is classified as an alkaline earth metal.
Properties
| Symbol | Be |
|---|---|
| Atomic number | 4 |
| Standard atomic weight | 9.0122 |
| Category | Alkaline earth metal |
| Group | 2 |
| Period | 2 |
| Electron configuration | [He] 2s2 |
| Outer-shell electrons | 2 |
The figure of 9.0122 is a standard atomic weight.
Calculate with beryllium
- Molar mass of any formula containing it
- Electron configuration, including ions
- Effective nuclear charge by Slater's rules
- Average atomic mass from isotope abundances
Group 2
Atomic weights are the IUPAC 2021 standard values, abridged to the conventional five significant figures. Group, period, category and electron configuration are derived from the atomic number rather than stored, so they cannot drift out of step with it.