The Lewis diagrams for \(\text{BF}_3\) and \(\text{NH}_3\) are shown below. Both molecules contain three single covalent bonds to peripheral atoms, but \(\text{NH}_3\) is polar with a nonzero dipole moment, whereas \(\text{BF}_3\) is nonpolar with a dipole moment of zero.

Which of the following statements best explains the difference in polarity between \(\text{BF}_3\) and \(\text{NH}_3\)?