Zinc vs Cadmium
Zinc and Cadmium 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 Cadmium wears.
Side by side
| Property | Zinc | Cadmium |
|---|---|---|
| Symbol | Zn | Cd |
| Atomic number (Z) | 30 | 48 |
| Atomic mass | 65.38 u | 112.41 u |
| Category | Transition metal | Transition metal |
| Group | 12 | 12 |
| Period | 4 | 5 |
| Phase at room temp | solid | solid |
| Electron configuration | [Ar] 3d^10 4s^2 | [Kr] 4d^10 5s^2 |
| Valence electrons | 2 | 2 |
| Atomic radius | 142 pm | 161 pm |
| Electronegativity | 1.65 | 1.69 |
| First ionisation energy | 906 kJ/mol | 868 kJ/mol |
The verdicts
- Bigger atom: Cadmium — the lower an element sits in its group, the more shells it wears.
- Greedy electron-taker: Cadmium — higher electronegativity means it pulls shared electrons harder.
- Heavier: Cadmium — 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.