 Discovered by In 1811 when Bernard Courtois ( )  Discovered while trying to make a poison not a cure  Tried discovering a weapon to use against Napoleon and his army

 Jean Lugol discovered that bonding iodine to a mineral (potassium) made it water soluble  Iodine naturally dissolves in alcohol, but not in water until it is first bonded to the elements potassium or chlorine.

 Swiss physician, Dr Jean François Condet announced that iodine could reduce goiters (enlarged thyroids).  People started using it whenever they felt sick (thought of as a “cure-all”)

 Atomic Number: 53  Atomic Symbol: I  Atomic Weight:  Electron Configuration:  Melting Point: o C  Boiling Point: 184 o C

 Iodine is a bluish-black solid that at room temperatures into a blue-violet gas with an irritating odor  It forms compounds with many elements, but is less active than the other halogens, which displace it from iodides.  It dissolves readily in chloroform, carbon tetrachloride, or carbon disulfide to form purple solutions.  It is only slightly soluble in water

 Iodine compounds are important in organic chemistry and very useful in medicine.  Thirty isotopes are recognized. Only one stable isotope, 127I is found in nature.  The artificial radioisotope 131I, with a half-life of 8 days, has been used in treating the thyroid gland.

 The most common compounds are the iodides of sodium and potassium (KI) and the iodates (KIO3).  Lack of iodine is the cause of goiter. Iodides, and thyroxin which contains iodine, are used internally in medicine, and as a solution of KI and iodine in alcohol is used for external wounds.  Potassium iodide finds use in photography. The deep blue color with starch solution is characteristic of the free element

 Care should be taken in handling and using iodine, as contact with the skin can cause lesions  Iodine vapor is intensely irritating to the eyes and mucous membranes.

 Chronic iodine deficiency can lead to numerous health problems in children and adults, including thyroid gland dysfunction (including goiter) and various neurologic, gastrointestinal, and skin abnormalities.

 Sumatra, Indonesia. This is a massive goiter caused by the continued lack of iodine (a micronutrient) in his diet. This is a condition both preventable and treatable with just pinches of iodized salt. But, unlike western countries, the sale of uniodized salt is not regulated in developing countries.  Picture from yahoo.com

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