7.(16) 3-Methyl-1-butene reacts with bromine under high temperature, [tex]\sim 350^{\circ} \mathrm{C}[/tex], to give [tex]1-[/tex] bromo-3-methyl-2-butene as the major product. Propose an acceptable mechanism that accounts for the formation of this product. Your answer must include each of the major steps of this chain reaction including the initiation and one of the terminations steps.

[tex]+\mathrm{Br}_2 \longrightarrow[/tex] heat [tex]\longrightarrow[/tex]
CC(C)=CCBr