The chemical symbol for the element iodine is "I." Iodine is a non-metal, and it belongs to Group 17 of the periodic table, known as the halogens. It is essential for human health, particularly for the production of thyroid hormones, which regulate metabolism, growth, and development. Iodine is most commonly found in marine environments, particularly in seawater and some fish species. It is also used in various applications, including antiseptics and contrast agents in medical imaging. Due to its importance in nutrition, some countries have implemented iodization of salt to prevent deficiencies among the population.