Astronomy · Chemical element
Selenium
Selenium (Se) is a chemical element belonging to the category Metalloid, with atomic number 34 and atomic mass 78.9710 u. This sheet describes its fundamental properties, periodic position and physical characteristics.
Identity
- Name: Selenium
- Symbol: Se
- Atomic number: 34
- Atomic mass: 78.9710 u
Position in the periodic table
- Group: 16
- Period: 4
- Category: Metalloid
Physico-chemical properties
- Standard state: Solid
- Melting point: 221 °C
- Boiling point: 685 °C
- Density: 4.81 g/cm³
- Electron configuration: [Ar] 3d¹⁰ 4s² 4p⁴
Scientific description
Selenium is a chemical element with symbol Se and atomic number 34. It belongs to the category of Metalloid and occupies group 16 and period 4. Its standard atomic mass is 78.9710 u.