Helium vs Polonium
| Property | He Helium | Po Polonium |
|---|---|---|
| Atomic number | 2 | 84 |
| Symbol | He | Po |
| Name | Helium | Polonium |
| Category | noble-gas | metalloid |
| Standard Atomic Weight | 4.002602 u | 209 u |
| Period | 1 | 6 |
| Group | 18 | 16 |
| Block | s | p |
| Phase at STP | gas | solid |
| Electron configuration | 1s2 | [Xe]6s24f145d106p4 |
| Oxidation states | [0] | [-2, 2, 4, 5, 6] |
| Electronegativity (Pauling) | N/A | 2 |
| Electron affinity | -0.5 eV | 1.9 eV |
| Density | 0.1785 kg/m³ | 9320 kg/m³ |
| Melting point | -272.2 °C | 253.85 °C |
| Boiling point | -268.93 °C | 961.85 °C |
| Discovery year | 1868 | 1898 |