Selenium
Reactive Nonmetal
Selenium (Se) is a chemical element with atomic number 34, classified as a reactive nonmetal. At room temperature it is a solid. It was discovered in 1817 by Jöns Jacob Berzelius.
Properties
- Atomic number
- 34
- Atomic mass
- 78.971 u
- Category
- Reactive Nonmetal
- Group
- 16
- Period
- 4
- Block
- p-block
- Electron configuration
- [Ar] 3d¹⁰ 4s² 4p⁴
- Phase at STP
- Solid
- Density
- 4.809 g/cm³
- Melting point
- 494 K (220.9 °C)
- Boiling point
- 958 K (684.9 °C)
- Electronegativity
- 2.55
- Atomic radius
- 103 pm
- Ionization energy
- 9.752 eV
- Discovery
- 1817 · Jöns Jacob Berzelius
Common uses
Glass manufacturing, photocopiers, solar cells, supplements
Did you know?
Essential trace element for humans and conducts electricity when exposed to light.