34 · Se
Selenium
Identified by Berzelius in 1817.
Identity
- Atomic number
- 34
- Symbol
- Se
- Canonical name
- Selenium
- Category
- nonmetal
- Group
- 16
- Period
- 4
- Block
- p
Properties
These quantities come from the Periodic Table JSON compilation. They have not yet been checked, one by one, against CIAAW atomic weights or NIST measurements. A value marked estimated is not a measurement.
- Atomic mass
- 78.9718 u
- Electron configuration
- [Ar] 3d10 4s2 4p4
- Electrons per shell
- 2, 8, 18, 6
- Standard state
- solid
- Density
- 4.81 g/cm³
- Melting point
- 494 K
- Boiling point
- 958 K
- Electronegativity
- 2.55 Pauling
- First ionization energy
- 941 kJ/mol
- Electron affinity
- 194.9587 kJ/mol
History
Residue from lead chambers
Discovery · confirmed · 1817
Berzelius identifies selenium in the mud from roasting pyrite.
Etymology
- Theme
- celestial body
- Language
- grec
- Root
- selene
- Meaning
- the Moon
Scientists
Places and institutions
- Stockholm — historical setting : Sweden — present country : Sweden
See also
Sources
- IUPAC, Periodic Table of the Elements
- Bowserinator, Periodic Table JSON. Compilation secondaire d’où viennent les grandeurs physiques importées (masse, densité, températures, énergies). Elles ne sont pas revérifiées une à une auprès du NIST ou de la CIAAW.
- John Emsley, Nature’s Building Blocks: An A–Z Guide to the Elements