History and uses:

     Iodine was discovered  by a French chemist Bernard Courtois in 1811. He discovered iodine while extracting sodium and potassium from seaweed ash. He gave sampled to his friends, Charles Bernard Desormes and Nicolas Clément to finish research. On November 29th, 1813, Desormes and Clément made Courtois' discovery public.

     Iodine is required in small amounts by humans. at one point, humans used Iodine as an antiseptic,  but due to its poisonous state, it is no longer used. Potassium iodine (KI) is used in making photographic film. When mixed with alcohol, iodine prevents diseases. Iodine is also added to salt, which is known as iodized salt.