Boron vs Aluminium
Boron and Aluminium sit in the same column of the periodic table — same family, one period apart — so almost every difference between them comes from one thing: the extra electron shell Aluminium wears.
Side by side
| Property | Boron | Aluminium |
|---|---|---|
| Symbol | B | Al |
| Atomic number (Z) | 5 | 13 |
| Atomic mass | 10.81 u | 26.982 u |
| Category | Metalloid | Post-transition metal |
| Group | 13 | 13 |
| Period | 2 | 3 |
| Phase at room temp | solid | solid |
| Electron configuration | [He] 2s^2 2p^1 | [Ne] 3s^2 3p^1 |
| Valence electrons | 3 | 3 |
| Atomic radius | 87 pm | 118 pm |
| Electronegativity | 2.04 | 1.61 |
| First ionisation energy | 801 kJ/mol | 578 kJ/mol |
The verdicts
- Bigger atom: Aluminium — the lower an element sits in its group, the more shells it wears.
- Greedy electron-taker: Boron — higher electronegativity means it pulls shared electrons harder.
- Heavier: Aluminium — 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.