Iodine is a solid at STP. Symbolized by I, iodine is a purple solid at STP. It belongs to Group 17, Period 5 of the Periodic Table.
Discovered by Bernard Courtois in 1811, iodine can be found in various species of seaweed. It is needed by humans for regulating body temperature and growth. Deficiency of iodine can lead to goitre, the swelling of the thyroid gland. Iodine is mainly derived from natural brine deposits and iodate minerals for various commercial purposes. Iodide salts are used in photographic chemicals, printing inks, catalysts, disinfectants and more. Small amounts of iodine are also added to table salts to prevent iodine deficiency.