17 Cl 35.45

Chlorine

diatomic nonmetal

Properties

Atomic number
17
Atomic mass
35.45 u
Category
diatomic nonmetal
Group
17
Period
3
Block
p-block
State (room temp)
Gas
Outer-shell electrons
7
Electronegativity
3.16 (Pauling)
Density
Melting point
-101.55 °C
Boiling point
-34.04 °C

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁵

Noble-gas shorthand: [Ne] 3s² 3p⁵

Electrons per shell: 2, 8, 7 — that's 7 in the outermost shell.

See how electron configuration is built →

Cl
Bohr model — outer-shell electrons in blue

About Chlorine

Chlorine is a chemical element with symbol Cl and atomic number 17. It also has a relative atomic mass of 35.5. Chlorine is in the halogen group (17) and is the second lightest halogen following fluorine.

Position in the periodic table

Open the interactive periodic table →

Data compiled from Wikipedia, PubChem, and IUPAC. Source.