Chlorine
Cl
The atomic number is 17 and the mass number is 35. The period number is 3, the group number is 17, and the group name is Halogens. It is a gas and a non-metal.
Disinfectant
Chlorine is currently used as a disinfectant for pools and to fight bacteria in that specific environment.
Chloroform
Chlorine was formerly used in chloroform and other medical uses before discovering it later resulted in cases of lung cancer.
Pousinous Gas
During the First World War, chloride gas was used against enemies and caused serious lung damage.