Se
Selenium
Element 34 · Nonmetal · Period 4, Group 16
Solid · Discovered 1817
Atomic Properties
| Atomic Number | 34 |
| Atomic Mass | 78.97u |
| Electron Configuration | [Ar]4s2 3d10 4p4 |
| Electronegativity | 2.55Pauling |
| Atomic Radius | 190pm |
| Ionization Energy | 9.752eV |
| Electron Affinity | 2.021eV |
| Oxidation States | +6, +4, -2 |
Physical Properties
| Standard State | Solid |
| Melting Point | 493.65K |
| Boiling Point | 958K |
| Density | 4.809g/cm³ |
| Group Block | Nonmetal |
| Year Discovered | 1817 |