Selenium vs Krypton
| Property | Se Selenium | Kr Krypton |
|---|---|---|
| Atomic number | 34 | 36 |
| Symbol | Se | Kr |
| Name | Selenium | Krypton |
| Category | nonmetal | noble-gas |
| Standard Atomic Weight | 78.971 u | 83.798 u |
| Period | 4 | 4 |
| Group | 16 | 18 |
| Block | p | p |
| Phase at STP | solid | gas |
| Electron configuration | [Ar]4s23d104p4 | [Ar]4s23d104p6 |
| Oxidation states | [-2, -1, 0, 1, 2, 3, 4, 5, 6] | [0, 1, 2] |
| Electronegativity (Pauling) | 2.55 | 3 |
| Electron affinity | 2.0206 eV | -1 eV |
| Density | 4809 kg/m³ | 3.733 kg/m³ |
| Melting point | 220.5 °C | -157.36 °C |
| Boiling point | 684.85 °C | -153.42 °C |
| Discovery year | 1817 | 1898 |