Chlorine is a reactive greenish-yellow halogen whose compounds include common salt and many essential disinfectants.
Atomic number
17
Category
Halogen
Period
3
Group
17
State
Gas
Fun facts about Chlorine
Chloride ions are abundant in seawater and body fluids.
Chlorine gas is toxic and must be handled in closed systems.
Controlled chlorination has greatly reduced water-borne disease.
Common uses of Chlorine
Drinking-water disinfection
PVC manufacture
Bleaching chemicals
Where Chlorine sits in the periodic table
Chlorine is classified as a halogen in period 3 and group 17 of the periodic table. Under the conditions represented in this reference, its state is gas.
Quick chemistry revision
For quick revision, pair the symbol Cl with atomic number 17 and the listed atomic mass 35.45. The summary, facts, and uses above keep those element properties together in one reference.