Potassium vs Erbium
| Property | K Potassium | Er Erbium |
|---|---|---|
| Atomic number | 19 | 68 |
| Symbol | K | Er |
| Name | Potassium | Erbium |
| Category | alkali-metal | lanthanide |
| Standard Atomic Weight | 39.0983 u | 167.259 u |
| Period | 4 | 6 |
| Group | 1 | N/A |
| Block | s | s |
| Phase at STP | solid | solid |
| Electron configuration | [Ar]4s1 | [Xe]6s24f12 |
| Oxidation states | [-1, 1] | [0, 1, 2, 3] |
| Electronegativity (Pauling) | 0.82 | 1.24 |
| Electron affinity | 0.5014 eV | 0.312 eV |
| Density | 890 kg/m³ | 9070 kg/m³ |
| Melting point | 63.38 °C | 1528.85 °C |
| Boiling point | 758.85 °C | 2867.85 °C |
| Discovery year | 1807 | 1843 |