Ba
Barium
Barium is a chemical element with the symbol Ba and atomic number 56. It has a standard atomic weight of 137.33, sits in period 6 and group 2, and is classified as an alkaline earth metal.
Properties
| Symbol | Ba |
|---|---|
| Atomic number | 56 |
| Standard atomic weight | 137.33 |
| Category | Alkaline earth metal |
| Group | 2 |
| Period | 6 |
| Electron configuration | [Xe] 6s2 |
| Outer-shell electrons | 2 |
The figure of 137.33 is a standard atomic weight.
Compounds containing barium
3 of the compounds in this reference contain Ba, listed by the fraction of their mass it makes up.
| Compound | Formula | Atoms | % by mass |
|---|---|---|---|
| barium hydroxide | BaH2O2 | 1 | 80.1% |
| barium chloride | BaCl2 | 1 | 66.0% |
| barium sulfate | BaO4S | 1 | 58.8% |
Calculate with barium
- 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.