---
title: "Aluminium (Al): Atomic Mass, Electron Configuration & Properties"
url: https://www.moldraw.com/elements/aluminium.html
description: "Aluminium (Al), element 13: atomic mass 26.982, electron configuration [Ne] 3s² 3p¹, group 13, period 3, p-block post-transition metal. Melting and boiling point, density, electronegativity and shells."
lang: en
publisher: Scidart Academy
generated: 2026-11-03
---
13Al26.982

# 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.

[Download periodic table PDF](https://www.moldraw.com/printables/periodic-table.pdf)[Open interactive periodic table](https://www.moldraw.com/tools/free-chem-tools/interactive-periodic-table.html)

## 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](https://www.moldraw.com/tools/free-chem-tools/electron-configuration-calculator.html).

## 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](https://www.moldraw.com/tools/free-chem-tools/molar-mass-calculator.html) for any formula containing Al.

## Position in the periodic table

Tap any element to open its page.

## 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](https://github.com/Bowserinator/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.