Atomic Number: 34

Name: Selenium

Atomic symbol: Se

Atomic Weight: 78.96

Electron affinity: -195 kJ/mol

Electron configuration: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁴

Ionization energies: 941 kJ/mol

Pauling electronegativity: 2.4

Melting Point: 217^oC

Boiling Point: 685^oC

Density: 4.81 g/cm³

Standard potential (volts), X + 2e^- ---> X^2-: -0.78

Covalent radius: 1.17 angstroms

Ionic radius: 1.84 angstroms (-2); 2.32 angstroms (-1); 0.66 angstroms (+1); 0.50 angstroms (+4); 0.42 angstroms (+6)

Van Der Wall's radius: 2.0 angstroms

Common oxidation states in compounds: -2, +4, +6