Iodine is the fourth element in Group 17 of the periodic table, a group of elements known as the halogens. Iodine has an atomic number of 53, and atomic mass of 126.9045, and a chemical symbol of I.

Properties

Iodine is a heavy, grayish black, metallic-looking solid which, when heated, does not melt but, instead, sublimes to give a beautiful violet vapor. If a cold object, such as an iron bar, is placed in the violet vapors, attractive, delicate, metallic crystals of iodine condense on the bar. If heated under pressure, iodine can be made to melt at a temperature of 236.3°F (113.5°C) and to boil at a temperature of 363°F (184°C). The element has a density of 4.98 grams per cubic centimeter. It is only slightly soluble in water, but it dissolves in many organic liquids, such as alcohol and carbon disulfide, to which it imparts a...