Helium vs Iodine
| Property | He Helium | I Iodine |
|---|---|---|
| Atomic number | 2 | 53 |
| Symbol | He | I |
| Name | Helium | Iodine |
| Category | noble-gas | halogen |
| Standard Atomic Weight | 4.002602 u | 126.90447 u |
| Period | 1 | 5 |
| Group | 18 | 17 |
| Block | s | p |
| Phase at STP | gas | solid |
| Electron configuration | 1s2 | [Kr]5s24d105p5 |
| Oxidation states | [0] | [-1, 1, 2, 3, 4, 5, 6, 7] |
| Electronegativity (Pauling) | N/A | 2.66 |
| Electron affinity | -0.5 eV | 3.059 eV |
| Density | 0.1785 kg/m³ | 4930 kg/m³ |
| Melting point | -272.2 °C | 113.7 °C |
| Boiling point | -268.93 °C | 184.4 °C |
| Discovery year | 1868 | 1811 |