53
Iodine
Atomic Number53
Atomic Mass126.90 u
CategoryHalogen
State at Room TempSolid
Year Discovered1811
About Iodine
Essential for thyroid hormone production. Iodine deficiency causes goiter and is the leading preventable cause of intellectual disability worldwide. Added to table salt in many countries since the 1920s. Used as a disinfectant and in photography. The name means violet in Greek from its purple vapor. Iodine-131 is a significant radioactive hazard from nuclear accidents.
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