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Post-transition metals

Aluminium

A lightweight, corrosion-resistant and abundant metal.

Atomic #13Mass26.982Blockp-blockPeriod3Group13
Al13 · 26.982
3D Atom Explorer

Inside the Aluminium atom

Switch between Bohr and Quantum Cloud modes to compare a simple teaching model with a more realistic probability-based view, and follow the guided tour to explore the Aluminium atom step by step.

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Electron configuration

[Ne] 3s2 3p1

A neutral Aluminium atom has 13 electrons (equal to its proton count). Choosing a different isotope above changes only the neutron count.

Shell distribution

Shell 12 e⁻Shell 28 e⁻Shell 33 e⁻

Electrons fill inner shells before outer ones; the outermost (valence) shell drives the element's chemistry.

Properties

Physical & atomic properties

State (room temp)
Solid
Melting point
933 K (660 °C)
Boiling point
2792 K (2519 °C)
Density
2.7 g/cm³
Electronegativity
1.61 Pauling
Atomic radius
125 pm
1st ionization energy
577 kJ/mol
Category
Post-transition metals
History

Discovery & naming

Discovered
1825
Discovered by
Hans Christian Ørsted
Origin of name
Latin 'alumen', for alum.

Notable uses

Aircraft, packaging, power lines, and construction.

Cosmic origin

Where Aluminium comes from

Stellar fusion and dying stars

Formed in the carbon- and neon-burning layers of massive stars and released by their explosions.

Simplified origin map — many elements form through more than one astrophysical pathway.

Summary

Atomic number
13
Atomic mass
26.982
Category
Post-transition metals
Group · Period
13 · 3
Block
p-block
Shells
2 · 8 · 3