Iodine is an element and, therefore, it is not strictly "made" of anything but iodine atoms, according to Jefferson Lab. Iodine is a solid at room temperature and occupies position 53 on the periodic table. It is classed as a member of the halogen group.
As its atomic number indicates, iodine atoms possess 53 protons that are surrounded by a shell of 53 electrons. These particles are kept stable by a number of neutrons that varies with the specific isotope. Though trace amounts of iodine are needed by the human body, pure iodine is poisonous and should be handled with caution.