Aluminum
POST-TRANSITION METAL · GROUP 13 · PERIOD 3
13
Al
Aluminum
26.982
Atomic Data
| Atomic Number | 13 |
| Symbol | Al |
| Atomic Weight | 26.982 u |
| Density (STP) | 2.7 g/cm³ |
| Melting Point | 660.32 °C (933.47 K) |
| Boiling Point | 2518.85 °C (2792 K) |
| Electronegativity | 1.61 (Pauling) |
| Electron Config. | 1s2 2s2 2p6 3s2 3p1 |
| Oxidation States | +3 |
| Phase at STP | Solid |
| Category | Post-Transition Metal |
| Period / Group | 3 / 13 |
| CAS Number | 7429-90-5 |
Electron Configuration
{{BOHR_SVG}}
[Ne] 3s2 3p1
| Shell | n | Subshell | Electrons | Cumulative |
|---|---|---|---|---|
| K | 1 | 1s | 2 | 2 |
| L | 2 | 2s | 2 | 4 |
| L | 2 | 2p | 6 | 10 |
| M | 3 | 3s | 2 | 12 |
| M | 3 | 3p | 1 | 13 |
| Total | 13 | 13 | ||
Isotopes of Aluminum
Aluminum is monoisotopic — ²⁷Al is its only naturally occurring stable isotope, accounting for 100% of all natural Aluminum.
| Isotope | Symbol | Protons | Neutrons | Abundance | Stability |
|---|---|---|---|---|---|
| Aluminum-27 | ²⁷Al | 13 | 14 | 100 | Stable |
Abundance & Occurrence
Aluminum is present in Earth's crust at approximately 82300 ppm by mass and at approximately 58 ppm by mass throughout the universe.
Earth's Crust (ppm by mass)
Aluminum
82300 ppm
Silicon (ref.)
277,000 ppm
Oxygen (ref.)
461,000 ppm
Universe (ppm by mass)
Aluminum
58 ppm
Helium (ref.)
230,000 ppm
Hydrogen (ref.)
739,000 ppm
Discovery & History
{{HISTORY_TIMELINE}}
Safety & Handling
-
{{SAFETY_BULLETS}}
Aluminum in the Real World
Real-World Uses
-
{{USES_LIST_ITEMS}}
Downloadable Resources
Free periodic table reference sheets for classrooms, study sessions, and laboratory use.