Strontium vs Barium
Strontium and Barium 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 Barium wears.
Side by side
| Property | Strontium | Barium |
|---|---|---|
| Symbol | Sr | Ba |
| Atomic number (Z) | 38 | 56 |
| Atomic mass | 87.62 u | 137.33 u |
| Category | Alkaline earth metal | Alkaline earth metal |
| Group | 2 | 2 |
| Period | 5 | 6 |
| Phase at room temp | solid | solid |
| Electron configuration | [Kr] 5s^2 | [Xe] 6s^2 |
| Valence electrons | 2 | 2 |
| Atomic radius | 219 pm | 253 pm |
| Electronegativity | 0.95 | 0.89 |
| First ionisation energy | 550 kJ/mol | 503 kJ/mol |
The verdicts
- Bigger atom: Barium — the lower an element sits in its group, the more shells it wears.
- Greedy electron-taker: Strontium — higher electronegativity means it pulls shared electrons harder.
- Heavier: Barium — 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.