Selenium

Atomic number34
Atomic weight78.96
Discovery (year)1818
Atomic radius (A)1.16
Melting point (oC)220.2
Boiling point (oC)684.9
Density (g/cm3)4.82
Specific heat (cal/g oC)0.084
Ionization potential (eV)9.752
Electron Affinity (eV)2.0206