Chemical element · Atomic number 13
Aluminum
Aluminum in the periodic table: atomic number 13, electron configuration, atomic mass, physical data, oxidation states, media credit and visible sources.
Post-transition metal
solid
26.981538 u
Documented element sampleSeveral pieces of elemental aluminium metal.
Image credit: W. Oelen
Auto-oriented, limited to 1600 × 1200 pixels and re-encoded as WebP; the subject was not altered.
Atomic classification
Shell occupancy
Aluminum in the Bohr shell model
This shows the electron distribution of the neutral atom in a simplified shell model.
- K · n=1
- 2 electrons
- L · n=2
- 8 electrons
- M · n=3
- 3 electrons
- Electron configuration
- [Ne]3s2 3p1
- Electrons per shell
- 2 · 8 · 3
- Group
- 13
- Period
- 3
- Block
- P
- Element category
- Post-transition metal
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Physical and chemical properties
- Atomic mass
- 26.981538 u
- Standard state
- solid
- Density
- 2.7 g/cm³
- Melting point
- 933.437 K
- Boiling point
- 2,792 K
- Electronegativity
- 1.61 (Pauling)
- First ionisation energy
- 5.986 eV
- Oxidation states
- +3
- Discovery
- known since antiquity
Safety and periodic classification
Safety
Safe handling cannot be inferred from Aluminum's position in the periodic table alone. Laboratory, classroom and disposal decisions must follow the documentation for the exact material and its safety data sheet.
Position and comparison
Aluminum is in period 3, group 13 and the P block. Its direct neighbours by atomic number are Magnesium and Silicon. The recorded Pauling electronegativity is 1.61. Periodic trends are compared only through the separately sourced neighbouring values.
Sources and scope
PubChem attributes element data to sources including IUPAC, NIST and IAEA. Quanta stores the referenced snapshot locally and leaves unknown values unavailable.