Copper vs Aluminium
Both carry electricity brilliantly — one heavy and orange-brown, the other light and silvery. Why do wires, pots and planes choose differently?
Side by side
| Property | Copper | Aluminium |
|---|---|---|
| Symbol | Cu | Al |
| Atomic number (Z) | 29 | 13 |
| Atomic mass | 63.546 u | 26.982 u |
| Category | Transition metal | Post-transition metal |
| Group | 11 | 13 |
| Period | 4 | 3 |
| Phase at room temp | solid | solid |
| Electron configuration | [Ar] 3d¹⁰ 4s¹ | [Ne] 3s^2 3p^1 |
| Valence electrons | 1 | 3 |
| Atomic radius | 145 pm | 118 pm |
| Electronegativity | 1.9 | 1.61 |
| First ionisation energy | 745 kJ/mol | 578 kJ/mol |
The verdicts
- Bigger atom: Copper — the lower an element sits in its group, the more shells it wears.
- Greedy electron-taker: Copper — higher electronegativity means it pulls shared electrons harder.
- Heavier: Copper — compare the atomic masses in the table above.
Want the visual version with bars for radius, electronegativity and ionisation energy? Open the interactive compare tool with this pair already loaded.