Potassium vs Fermium
| Property | K Potassium | Fm Fermium |
|---|---|---|
| Atomic number | 19 | 100 |
| Symbol | K | Fm |
| Name | Potassium | Fermium |
| Category | alkali-metal | actinide |
| Standard Atomic Weight | 39.0983 u | 257 u |
| Period | 4 | 7 |
| Group | 1 | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Ar]4s1 | [Rn] 5f12 7s2 |
| Oxidation states | [-1, 1] | [2, 3] |
| Electronegativity (Pauling) | 0.82 | 1.3 |
| Electron affinity | 0.5014 eV | 0.339 eV |
| Density | 890 kg/m³ | 9700 kg/m³ |
| Melting point | 63.38 °C | 1526.85 °C |
| Boiling point | 758.85 °C | -273.15 °C |
| Discovery year | 1807 | 1952 |