Iodine is classified as a non-metal and a halogen. It belongs to Group 17 of the periodic table, which includes the halogens such as fluorine, chlorine, bromine, and astatine.
As a non-metal, iodine exhibits properties typical of this category, including brittleness in its solid state and the ability to gain electrons during chemical reactions. In its elemental form, iodine is most commonly found as a diatomic molecule (I2). It appears as a dark gray or purplish-black solid that sublimates into violet gas when heated.
Iodine plays a crucial role in various biological processes, particularly in the synthesis of thyroid hormones, which are essential for regulating metabolism. Due to its unique properties and essential biological functions, iodine is a significant element in both inorganic and organic chemistry.