Iodine undergo sublimation i.e.directly changes into gaseous state without melting.
Group 17 elements
Group 17 elements are collectively called as halogens, and they are reactive non-metals include fluorine, chlorine, bromine, and iodine.
The term sublimation is the passage or the transformation or conversion that substances undergo when passing from one state to another, for example from a solid substance to gas.
A range of solids, including water, iodine, arsenic, and solid carbon dioxide (dry ice), can sublimate at normal temperatures and pressures. Other materials can sometimes be made to sublimate by creating conditions of low pressure.