Explain reactivity of halogens with metals.

Explanation

Halogens react with metals to form metal halides. For example, bromine reacts with magnesium to give magnesium bromide.
`Mg(s) + Br_(2)(l) to MgBr_(2)(s)`
Order of reactivity of Halogens: `F_(2) gt Cl_(2) gt Br_(2) gt I_(2)`
The ionic character of the halides decreases in the order MF > MCI > MBr > MI where M is a monovalent metal.
For example: `overset(NaF gt NaCl gt NaBr gt Nal)underset("Ionic character decreases")to`
If a metal exhibits more than one oxidation state, the halides in higher oxidation state will be more covalent than the one in lower oxidation state.
For example: `SnCl_4, PbCl_4, SbCl_5` and `UF_6` are more covalent than `SnCl_2, PbCl_2, SbCl_3` and `UF_4` respectively.