How does fluorine (f) differ from iodine (i)?

Explanation:

Both fluorine and iodine are non-metals. As it is known that when we move down the group there will be decrease in reactivity.

Hence, reactivity of fluorine is much more than the reactivity of iodine.

Also, fluorine is smaller in size as compared to iodine atom due to this nucleus of fluorine is able to strongly pull the electrons more towards itself.

Whereas nucleus of iodine atom is shielded by electron shells due to which it is not able to strongly pull the electrons from a donor atom.  

Also, fluorine is present in gaseous state at room temperature and iodine exists as a solid at room temperature.