We know that in the periodic table Fluorine [ F = 3.98 ] is the most electronegative element. So it signifies that Fluorine only need 1 electron to fill it outermost shell and complete their stability.
So Fluorine can forms the bond by the Noble gases configuration of Iodine .
But on the other hand Chlorine and Bromine are not enough electronegative to achieve that much of stability and form stable bond with the noble gas configuration of iodine.
