Al
Aluminium
Aluminium is a chemical element with the symbol Al and atomic number 13. It has a standard atomic weight of 26.982, sits in period 3 and group 13, and is classified as a post-transition metal.
Properties
| Symbol | Al |
|---|---|
| Atomic number | 13 |
| Standard atomic weight | 26.982 |
| Category | Post-transition metal |
| Group | 13 |
| Period | 3 |
| Electron configuration | [Ne] 3s2 3p1 |
| Outer-shell electrons | 3 |
The figure of 26.982 is a standard atomic weight.
Compounds containing aluminium
4 of the compounds in this reference contain Al, listed by the fraction of their mass it makes up.
| Compound | Formula | Atoms | % by mass |
|---|---|---|---|
| lithium aluminium hydride | AlH4Li | 1 | 71.1% |
| aluminium oxide | Al2O3 | 2 | 52.9% |
| aluminium chloride | AlCl3 | 1 | 20.2% |
| aluminium sulfate | Al2O12S3 | 2 | 15.8% |
Calculate with aluminium
- 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 13
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.