Calcium vs Francium
| Property | Ca Calcium | Fr Francium |
|---|---|---|
| Atomic number | 20 | 87 |
| Symbol | Ca | Fr |
| Name | Calcium | Francium |
| Category | alkaline-earth-metal | alkali-metal |
| Standard Atomic Weight | 40.078 u | 223 u |
| Period | 4 | 7 |
| Group | 2 | 1 |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Ar]4s2 | [Rn]7s1 |
| Oxidation states | [1, 2] | [1] |
| Electronegativity (Pauling) | 1 | 0.7 |
| Electron affinity | 0.0245 eV | 0.491 eV |
| Density | 1540 kg/m³ | 1870 kg/m³ |
| Melting point | 841.85 °C | 26.85 °C |
| Boiling point | 1483.85 °C | -273.15 °C |
| Discovery year | 1808 | 1939 |