Halogens react with metals to form metal halides. The halogen atoms gain electrons to form halide ions (chloride, bromide or iodide) and the metal atoms lose electrons to form positive ions, so the products are ionic compounds. For example, sodium burns in chlorine to make sodium chloride: 2Na + Cl2 → 2NaCl. Hot iron wool glows brightly in chlorine and forms iron(III) chloride: 2Fe + 3Cl2 → 2FeCl3.
Bromine and iodine react with metals in the same way, to give bromides and iodides, but less vigorously. The reactivity of the halogens decreases down the group. Chlorine reacts most vigorously, bromine is slower and iodine is slower still.
Using this pattern, fluorine should react even more vigorously than chlorine, and astatine should react least vigorously of all the halogens.