Question

the carbon-halogen bond has got to be broken because that gets easier as you go from fluoride to chloride to bromide to iodide, the compounds get more reactive in that order. Why then does the boiling point also increase shouldn't they decrease if its easier to break the bonds like for there reactivity.

Answer 1

No. Iodine has more electrons, but core electrons do not cause van der waal's interactions.
The carbon-fluorine bond is polarised. The classic reaction of haloalkanes is nucleophilic substitution by a nucleophile attacking the C-X antibonding orbital. I assume this is A level, so the simple answer is that because the C-F bond is polarised more than the C-Cl one, it's more attractive to a nucleophile, so the compound is more reactive.