Question

Of the molecules sif4 and sibr4, which has bonds that are more polar

Answer 1

Of SiF4 and SiBr4, the atom SiF4 is more polar. This is because the cation of both molecules are Silicon, but the anions of each are different. In SiF4, the anion is Fluorine, which is more electronegative than the Bromine in SiBr4, which creates a larger dipole, which results in a more polar molecule.