34
78.97
Se
Selenium
Identification
CAS Number: 7782-49-2
Discovery Year: 1818
Discoverer: Jöns Berzelius
Discovery Location: Sweden
Properties
Atomic Dimensions
Atomic Radius: 115 pm →
Atomic Radius (Rahm): 224.00000000000003 pm
Covalent Radius: 120 pm →Van der Waals Radius: 190 pm
Metallic Radius: 117 pm
Atomic Volume: 16.5 cm³/mol
Lattice Constant: 4.36 Å
Thermodynamics
Electronic Structure
Electron Config: [Ar] 3d10 4s2 4p4
Block: p
Period: 4 →Group: 16 →Electronegativity: 2.55 →Electron Affinity: 2.02067 eV →Oxidation States: -2, +4, +6
Abundance & Geochemistry
Crust Abundance: 0.05 mg/kg
Sea Abundance: 0.0002 mg/L
Geochemical Class: semi-volatile
Goldschmidt Class: chalcophile
About
Metalloid element, belongs to group 16 of the periodic table. Multiple allotropic forms exist. Chemically resembles sulphur. Discovered in 1817 by Jons J. Berzelius.
Isotopes
Se-80 80 49.80%
Se-78 78 23.69%
Se-76 76 9.23%
Se-82 82 8.82%
Se-77 77 7.60%
Se-74 74 0.8600%
