| Atomic Number: | 34 |
| Element Symbol: | Se |
| Element Name: | Selenium |
| Atomic Weight: | 78.96 |
| Group Number: | 16 |
| Group Name: | Chalcogen |
| Period Number: | 4 |
| Block: | p-block |
| Ground State Configuration: | [Ar] 3d10 4s2 4p4 |
| Ground State Level: | 3P2 |
| Standard State: | Solid |
| Common Valences: | 2,4,6 |
| Bond Length: | 232.1 |
| Atomic Radius Empirical: | 115 |
| Atomic Radius Calculated: | 103 |
| Covalent Radius Empirical: | 116 |
| Vander Waals Radius: | 190 |
| Electron Affinity: | 195.0 |
| First Ionization Energy: | 941.0 |
| Pauling Electronegativity: | 2.55 |
| Sanderson Electronegativity: | 3.01 |
| Allred Rochow Electronegativity: | 2.48 |
| Mulliken Jaffe Electronegativity: | 2.60 |
| Allen Electronegativity: | 2.424 |
| Density Of Solid: | 4819 |
| Molar Volume: | 16.42 |
| Velocity Of Sound: | 3350 |
| Youngs Modulus: | 10 |
| Rigidity Modulus: | 3.7 |
| Bulk Modulus: | 8.3 |
| Poissons Ratio: | 0.33 |
| Mineral Hardness: | 2.0 |
| Brinell Hardness: | 736 |
| Electrical Resistivity: | high |
| Refractive Index: | 1.000895 |
| Melting Point: | 221 |
| Boiling Point: | 685 |
| Critical Temperature: | 1493 |
| Thermal Conductivity: | 0.52 |
| Enthalpy Of Fusion: | 5.4 |
| Enthalpy Of Vaporization: | 26 |
| Enthalpy Of Atmization: | 227 |
| Most Common Oxidation Numbers: | 6,4,2,-2 |
| Color: | Grey, metallic lustre |
| Classification: | Non-metallic |
| Discovered By: | Jons Berzelius |
| Discovered At: | Sweden |
| Discovered When: | 1817 |
| Origin Of Name: | From the Greek word selene meaning moon |
Calculate the molecular weight of Selenium or molecular weight Se.
Also see the full list of chemical elements and atomic weights.