Chlorine and its family: the halogens
At the right hand side of Mr Mendeleevs Periodic Table of the chemical element, you find a family of chemical elements: the halogens. They are called fluorine, chlorine, bromine and iodine. Like chlorine, the other halogens are so reactive that you don't find them freely in nature.
But chemists can isolate the pure halogens from different compounds they are in. And then... strange things can happen!
You will find the halogens in the second-right column of the Periodic Table.
Watch this video.