Aluminium (Al) – element 13
Aluminium is a chemical element with the symbol Al and atomic number 13. It is a post-transition metal in group 13, period 3 of the periodic table (p-block), and is a solid at room temperature.
Aluminium (Al) has atomic number 13, atomic mass 26.982 u and electron configuration [Ne] 3s2 3p1.
Aluminium facts
| Symbol | Al |
|---|---|
| Atomic number | 13 |
| Atomic mass | 26.982 u (g/mol) |
| Category | post-transition metal |
| Group | group 13 |
| Period | 3 |
| Block | p-block |
| Phase at 20 °C | Solid |
| Electron configuration | 1s2 2s2 2p6 3s2 3p1 |
| Noble-gas notation | [Ne] 3s2 3p1 |
| Electrons per shell | 2, 8, 3 |
| Valence electrons | 3 |
Bohr model and shells
Aluminium has 13 electrons in 3 shells: 2, 8, 3. Full configuration and noble-gas notation are in the table; work out any element or ion with the electron configuration calculator.
Physical and atomic properties
| Melting point | 933.47 K (660.3 °C) |
|---|---|
| Boiling point | 2743 K (2469.8 °C) |
| Density | 2.7 g/cm³ |
| Electronegativity (Pauling) | 1.61 |
| Electron affinity | 41.762 kJ/mol |
| Ionization energies | 577.5, 1816.7, 2744.8 kJ/mol (1st, 2nd, 3rd) |
| Molar heat capacity | 24.2 J/(mol·K) |
Use the atomic mass in the molar mass calculator for any formula containing Al.
Position in the periodic table
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Frequently asked questions
What is the atomic mass of aluminium?
The atomic mass of aluminium is 26.982 u, so one mole of aluminium atoms weighs 26.982 g.
What is the electron configuration of aluminium?
Aluminium has 13 electrons: 1s² 2s² 2p⁶ 3s² 3p¹, or [Ne] 3s² 3p¹ in noble-gas notation. Electrons per shell: 2, 8, 3.
How many valence electrons does aluminium have?
Aluminium has 3 valence electrons (group 13).
Is aluminium a metal?
Yes. Aluminium is a post-transition metal.
Where is aluminium on the periodic table?
Aluminium is in group 13, period 3, in the p-block.
Data: Periodic-Table-JSON (CC BY-SA 3.0); standard atomic weights from IUPAC (abridged). Values in brackets are the mass number of the longest-lived isotope.