Aluminium Element Properties
Complete reference for Aluminium (Al, element 13): atomic data, electron configuration, isotopes, physical constants, and chemical behavior.
Aluminium
Post-transition Metal — Period 3, Group 13
Atomic Identity
Electron Configuration
1 unpaired electron in 3p
Notable Isotopes of Aluminium
| Isotope | Protons | Neutrons | Mass (u) | Natural Abundance | Stability |
|---|---|---|---|---|---|
| ²⁷Al | 13 | 14 | 26.98153853 | 100% | Stable |
| ²⁶Al | 13 | 13 | 25.98689190 | Trace |
Unstable
Radioactive — β⁺/EC, t½ = 7.17×10⁵ yr |
| ²⁸Al | 13 | 15 | 27.98191 | Synthetic |
Unstable
Radioactive — β⁻, t½ = 2.245 min |
| ²⁴Al | 13 | 11 | 23.99994 | Synthetic |
Unstable
Radioactive — β⁺, t½ = 2.053 s |
²⁷Al is the only naturally occurring stable isotope, making aluminium essentially monoisotopic.
Physical Properties
Chemical Properties
Ground State Quantum Numbers
Key Spectral Emission Lines
Key Facts About Aluminium
Most Abundant Metal
Aluminium is the most abundant metal in Earth's crust, making up about 8.2% by mass. It is the third most abundant element overall, after oxygen and silicon.
Lightweight Strength
With a density of 2.70 g/cm³ — about one-third that of steel — aluminium provides exceptional strength-to-weight ratio, making it essential in aerospace and automotive industries.
Natural Passivation
Aluminium spontaneously forms a thin, tenacious aluminium oxide (Al₂O₃) layer on its surface that prevents further oxidation and gives the metal excellent corrosion resistance.
Excellent Conductor
Aluminium has an electrical conductivity about 61% that of copper, but is far lighter. This makes it cost-effective for power transmission lines and electrical wiring.
Fully Recyclable
Aluminium can be recycled indefinitely without loss of properties. Recycling requires only about 5% of the energy needed to produce primary aluminium from bauxite ore.
Amphoteric Behavior
Aluminium is amphoteric — it reacts with both strong acids and strong bases. It dissolves in HCl to form AlCl₃ and in NaOH to form aluminate (Al(OH)₄⁻), producing hydrogen gas in both cases.
Summary
Complete reference for Aluminium (Al, element 13): atomic data, electron configuration, isotopes, physical constants, and chemical behavior.
How it works
- Browse the atomic identity section for symbol, atomic number, and standard atomic weight.
- Check the electron configuration panel for orbital notation and quantum numbers.
- Review the isotopes table for naturally occurring and notable radioactive isotopes.
- Consult the physical properties panel for melting point, boiling point, density, and state at STP.
- Use the chemical properties section to understand reactivity, oxidation states, and electronegativity.
- Copy any value with one click for use in reports or calculations.
Use cases
- Look up aluminium constants for chemistry homework or exams.
- Verify atomic data when writing lab reports or research papers.
- Reference isotope masses for nuclear chemistry calculations.
- Check thermodynamic constants for materials science or engineering work.
- Teach or learn the structure of the periodic table at element 13.
- Confirm electron configuration before writing molecular orbital diagrams.
- Compare aluminium properties for alloy design or materials selection.
- Quick-reference electronegativity and ionization energies for bond analysis.