013Post-transition metal · Group 13 · Period 3
Aluminium
Aluminium (Al) is element 13, a post-transition metal in the p-block — group 13, period 3. It is a solid at room temperature with 3 electron shells (2, 8, 3) and an atomic mass of 26.98153857 u.
- Atomic mass
- 26.98 u
- Phase · STP
- solid
- Melting
- 933 K · 660 °C
- Boiling
- 2743 K · 2470 °C
- Electronegativity
- 1.61
- Density
- 2.7 g/cm³
Photograph — Jurii, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons, source: https://images-of-elements.com/aluminium.php
Identity
- Atomic number
- 13
- Standard atomic weight
- 26.98 u
- Category
- Post-transition metal
- Group
- 13
- Period
- 3
- Block
- p-block
- Oxidation states
- +3
Physical properties
- Melting point
- 933 K · 660 °C
- Boiling point
- 2743 K · 2470 °C
- Density
- 2.7 g/cm³
- Molar heat capacity
- 24.2 J/(mol·K)
- Atomic radius
- 184 pm
- Electron affinity
- 41.762 kJ/mol
Atomic structure
13protons
14neutrons
13electrons
3valence e⁻
- Noble-gas notation
- [Ne] 3s2 3p1
- Full configuration
- 1s2 2s2 2p6 3s2 3p1
- Electrons per shell
- 2, 8, 3
Periodic trends
Where Aluminium ranks across all 118 elements.
Ionization energies
Energy to remove each successive electron (kJ/mol).
577.51
1.8k2
2.7k3
11.6k4
14.8k5
18.4k6
23.3k7
27.5k8
31.9k9
38.5k10
Successive ionization energies (kJ/mol, log scale).
Discovery
- Discovered
- Ancient
- Discovered by
- —
- Named by
- Humphry Davy
- Appearance
- silvery gray metallic