17 Cl

Halogen

Chlorine

Disinfects water; in table salt.

See it in the interactive periodic table

Properties of Chlorine

Atomic number (Z)
17
Symbol
Cl
Atomic mass
35.45 g/mol
Category
Halogen
Group
17
Period
3
Electron configuration
[Ne] 3s² 3p⁵
Electronegativity (Pauling)
3.16
Atomic radius
79 pm
First ionization energy
1251 kJ/mol
Melting point
171.6 K (-101.5 °C)
Boiling point
239.11 K (-34.0 °C)
Density
0.003214 g/cm³
Phase at 25 °C
Gas
Discovered
Discovered in 1774
← Browse all 118 elements