Krypton vs Francium
| Property | Kr Krypton | Fr Francium |
|---|---|---|
| Atomic number | 36 | 87 |
| Symbol | Kr | Fr |
| Name | Krypton | Francium |
| Category | noble-gas | alkali-metal |
| Standard Atomic Weight | 83.798 u | 223 u |
| Period | 4 | 7 |
| Group | 18 | 1 |
| Block | p | s |
| Phase at STP | gas | solid |
| Electron configuration | [Ar]4s23d104p6 | [Rn]7s1 |
| Oxidation states | [0, 1, 2] | [1] |
| Electronegativity (Pauling) | 3 | 0.7 |
| Electron affinity | -1 eV | 0.491 eV |
| Density | 3.733 kg/m³ | 1870 kg/m³ |
| Melting point | -157.36 °C | 26.85 °C |
| Boiling point | -153.42 °C | -273.15 °C |
| Discovery year | 1898 | 1939 |