Briefly explain your mechanism choice. S N 1 and S N 2 refer to nucleophilic substitution at a carbon atom, so they do not apply here. An associative mechanism involves adding a new ligand before the old one departs. Thus, a dissociative mechanism is most probable. However, an associative mechanism might operate, depending upon how readily Fe can violate the 18 electron rule.
Alkenes have p electrons availble to share with electron-poor electrophiles.
These same p electrons would repel electron-rich nucleophiles. Very briefly explain. Write a mechanism step which clearly illustrates your choice. Simple radicals are usually considered to be electrophilic because they have open octets. This is an E1 reaction, because there is no strong base present.