Selenium vs Iodine
| Property | Se Selenium | I Iodine |
|---|---|---|
| Atomic number | 34 | 53 |
| Symbol | Se | I |
| Name | Selenium | Iodine |
| Category | nonmetal | halogen |
| Standard Atomic Weight | 78.971 u | 126.90447 u |
| Period | 4 | 5 |
| Group | 16 | 17 |
| Block | p | p |
| Phase at STP | solid | solid |
| Electron configuration | [Ar]4s23d104p4 | [Kr]5s24d105p5 |
| Oxidation states | [-2, -1, 0, 1, 2, 3, 4, 5, 6] | [-1, 1, 2, 3, 4, 5, 6, 7] |
| Electronegativity (Pauling) | 2.55 | 2.66 |
| Electron affinity | 2.0206 eV | 3.059 eV |
| Density | 4809 kg/m³ | 4930 kg/m³ |
| Melting point | 220.5 °C | 113.7 °C |
| Boiling point | 684.85 °C | 184.4 °C |
| Discovery year | 1817 | 1811 |