13
Al
Aluminum
26.9815385
Aluminum (Al)
Post-Transition MetalGroup 13Period 3p-block-block
Aluminium (or aluminum; see different endings) is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, soft, nonmagnetic, ductile metal. Aluminium is the third most abundant element (after oxygen and silicon), and the most abundant metal, in the Earth's crust.
Latin name: Aluminium
Atomic Number
13
Atomic Mass
26.9815385 g/mol
Phase (STP)
Solid
Electron Config.
[Ne] 3s² 3p¹
General
SymbolAl
Atomic Number13
Atomic Mass26.9815385 g/mol
CategoryPost-Transition Metal
Group13
Period3
Blockp-block
Electron Configuration[Ne] 3s² 3p¹
Valence Electrons3
ColourSilvery-gray
Appearancesilvery gray metallic
CAS NumberCAS7429-90-5
Physical Properties
Phase (STP)Solid
Density2.7 g/cm³
Melting Point660.32°C · 1220.58°F · 933.47 K
Boiling Point2518.85°C · 4565.93°F · 2792.00 K
Atomic Properties
Atomic Radius118 pm
Covalent Radius121 pm
Van der Waals Radius184 pm
Electronegativity1.61 Pauling
Ionization Energy578 kJ/mol
Electron Affinity42.5 kJ/mol
Oxidation States+1, +2, +3
Ion ChargeAl³⁺
Thermodynamic
Molar Heat24.2 J/(mol·K)
Thermal Conductivity235 W/(m·K)
Electromagnetic
Electrical TypeConductor
Crystal Structure
Crystal StructureFace-centered cubic
Mechanical Properties
Mohs Hardness2.75
Abundance
In Universe0.0050%
In Sun0.00005999999999999999%
In Earth's Crust8.2000%
In Oceans0.0000002%
In Humans0.0087%
In Meteorites0.9100%
Discovery & History
Discovery Year1825
Discovered ByHans Christian Ørsted
Named ByHumphry Davy
Isotopes of Aluminum
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Al-26 | — | 7.17 × 10⁵ years | β⁺, EC |
| Al-27 | 100% | Stable | — |