Fluorine is the most reactive element of all in Group 7. You can see the trend in reactivity if you react the halogens with iron wool. Halogen Reaction with iron wool Fluorine Reacts with almost ...

Chlorine, bromine and iodine are the three common Group 7 elements. Group 7 elements form salts when they react with metals. The term ‘halogen’ means ‘salt former’.