Aluminium (Al): electron configuration, atomic mass and facts
Aluminium (also spelled aluminum) (Al) is element 13 of the periodic table, a post-transition metal in period 3, group 13. Its electron configuration is [Ne] 3s2 3p1, with electrons arranged in shells 2, 8, 3, and its standard atomic weight is 26.982 u.
💡 The most abundant metal in Earth’s crust.
▶ Watch Aluminium’s electrons orbit in the interactive periodic tableAluminium at a glance
| Symbol | Al |
|---|---|
| Atomic number | 13 |
| Atomic mass | 26.982 u |
| Category | Post-transition metal |
| Group | 13 |
| Period | 3 |
| Block | p-block |
| Electron configuration | 1s2 2s2 2p6 3s2 3p1 |
| Noble-gas shorthand | [Ne] 3s2 3p1 |
| Electrons per shell | 2, 8, 3 |
| Outer-shell electrons | 3 |
| Electronegativity (Pauling) | 1.61 |
| State at 20 °C | solid |
Experiments with aluminium
Where is Aluminium on the periodic table?
Aluminium is in period 3, group 13, in the p-block. The period number matches its 3 electron shells, and the block names the subshell its last electrons fill. In the same group, Boron sits directly above it and Gallium sits directly below it. Elements in one group have the same number of outer-shell electrons (3 here), which is why they react in similar ways.
How to work out the electron configuration of Aluminium
Put 13 electrons into subshells in order of rising energy, filling each before starting the next: 1s² (2), 2s² (4), 2p⁶ (10), 3s² (12), 3p¹ (13). In shorthand, [Ne] stands for the 10 electrons of neon, giving [Ne] 3s² 3p¹.
How electronegative is Aluminium?
Aluminium has a Pauling electronegativity of 1.61, ranking 50 of the 100 elements with a known value (fluorine is highest at 3.98). That is in the middle of the range.
Aluminium in the virtual lab
Faradium’s chemistry workbench includes these chemicals that contain aluminium: Aluminium foil, Aluminium sulfate. Open the Chemistry Lab to experiment with them.
Frequently asked questions
What is the electron configuration of Aluminium?
The electron configuration of Aluminium (Al) is 1s2 2s2 2p6 3s2 3p1. In noble-gas shorthand it is written [Ne] 3s2 3p1.
How many electrons does Aluminium have in each shell?
Aluminium has 13 electrons arranged in shells as 2, 8, 3. It has 3 electrons in its outer shell.
What is the atomic mass of Aluminium?
The standard atomic weight of Aluminium is 26.982 u, so one mole of Aluminium atoms has a mass of about 26.982 g.
Is Aluminium a metal?
Yes. Aluminium is a post-transition metal.
Explore nearby elements
More post-transition metals: Gallium, Indium, Tin, Thallium, Lead, Bismuth. See all elements on the periodic table.