Selenium |
| Symbol | Se |
|---|---|
| Latin name | Selenium |
| Atomic number | 34 |
| Period | 4 |
| Element category | Nonmetals |
| Relative atomic mass | 78.96 |
| Group | VI.A |
| Electronegativity | 2.4 |
| Oxidation numbers | -2, 2, 4, 6 |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p4 |
| Density [g/cm3] | 4.80 |
| State | Solid |
| Melting point [°C] | 217 |
| Boiling point [°C] | 685 |
| Critical point [°C] | 1493 |
| Critical pressure [MPa] | 27.2 |
| Thermal conductivity [W m-1K-1] | 2.04 |
| Heat capacity [J K-1g-1] | 0.32 |
| Discovery | 1817 |
| Hardness [Mohs scale] | 2.0 |
| Brinell hardness [MPa] | 736 |
| Young's modulus [GPa] | 10 |
| Electrical conductivity [S m-1] | 8 · 106 |
| Shear modulus [GPa] | 3.7 |
| 1.st ionization energy [eV] | 9.7524 |
| 2.nd ionization energy [eV] | 21.19 |
| 3.rd ionization energy [eV] | 30.82 |
| Stable isotopes | 6 |
| Unstable isotopes | 14 |