34
78.971 u
Se
Selenium
Nonmetal
Atomic Structure
Physical State
Group
16
Period
4
Block
p
Electron Configuration
[Ar] 3d¹⁰ 4s² 4p⁴
Physical Properties
Atomic Mass:
78.971 u
Electronegativity:
2.55
Atomic Radius:
190 pm
Ionization Energy:
9.752 eV
Density:
4.809 g/cm³
Melting Point:
494 K
Boiling Point:
958 K
Historical Information
Discovered By:
Jöns Jacob Berzelius
Year Discovered:
1817