ElementsWhat is aluminium?
Aluminium is the most common metal in the Earth's crust. It is light, does not rust away, and carries heat and electricity well. It is made from the ore bauxite, using a great deal of electricity.
What is aluminium used for?
Drink cans, kitchen foil, cooking pots, window frames, aircraft and vehicle bodies, and overhead power lines.
Where the name comes from
From alum, a salt known since ancient times. It is spelled aluminium in most of the world and aluminum in the United States.
Key facts
- Symbol
- Al
- Atomic number
- 13
- Atomic mass
- 26.981538 u
- Family
- Post-transition metal
- Period
- 3
- Group
- 13
- Block
- p
- State at room temperature
- Solid
- Melting point
- 660.3 °C (933.44 K, 1,221 °F)
- Boiling point
- 2,519 °C (2,792 K, 4,566 °F)
- Density
- 2.7 g/cm³
- Electrons per shell
- 2, 8, 3
- Electron configuration
- [Ne]3s2 3p1
- Common oxidation states
- +3
- Electronegativity (Pauling)
- 1.61
- First ionisation energy
- 5.986 eV
- Electron affinity
- 0.441 eV
- Atomic radius (van der Waals)
- 184 pm
- Discovered
- 1825
Place in the periodic table
Aluminium is element number 13. It sits in period 3 (row 3) of the periodic table, in group 13 (column 13), and belongs to the p-block. Just before it comes magnesium (12), and just after it comes silicon (14). In the same column, boron is above it and gallium is below it. Elements in one column tend to behave alike.
Family: Post-transition metals.
Physical properties
At room temperature aluminium is a solid. It melts at 660.3 °C and boils at 2,519 °C, so it stays liquid over a range of 1,859 degrees. Its density is 2.7 grams per cubic centimetre, so a one-litre block would weigh about 2.7 kilograms. By density it ranks 71st among the 96 elements with a measured value.
Inside the atom
An atom of aluminium has 13 protons in its nucleus and, when neutral, 13 electrons around it. The electrons are arranged in 3 shells: 2, 8, 3. The outermost shell holds 3 electrons. Written in full, the electron configuration is [Ne]3s2 3p1.
Its electronegativity on the Pauling scale is 1.61. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 5.986 electronvolts (about 578 kilojoules per mole). One mole of aluminium weighs 26.981538 grams, so a single gram contains about 2.23 × 1022 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains aluminium with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.