Iodine has 74 neutrons, 53 protons and 53 electrons, giving it an atomic mass of 126.9. While solid at room temperature with a density of 4.93 grams per cubic centimeter, iodine melts at 236.7 degrees Fahrenheit and boils at 364 degrees Fahrenheit.
Iodine, a nonmetal element in the halogen group, is found naturally in ocean water and some ocean plant species. It is an essential mineral for the human body, forming the base of thyroxin, an important hormone produced by the thyroid. Iodine is used in various forms and applications, such as in photographic films and testing chemicals, as well as medical uses, including as an antibacterial and in thyroid medications.