1. Electronegativity differences give us a sense of a bond's polarity. Which of the following bonds would you expect to be most nonpolar: C-O, C-Si, C-B, or C-S?

Question

Answer

my first anwer was C-O

C-B

C-S

my answer C-Si

can you explain a little further on what they mean by most nonpolar please.

Answer 1

The electronegativity gives an indication of how much the atom attracts electrons. When the difference is relatively high (as in HF; H is about 2.1 and F about 4.0; the difference is about 3 which means the electrons reside closer to the F atom than they do to the H atom; therefore, F carries a slightly negative charge and the H a slightly positive charge. That makes a dipole of the HF molecule. A dipole is just a molecule with one end slightly positive and the other end slightly negative. A non-polar bond is one in which the electrons are shared more equally and there is no separation of charge. NtriplebondN, for example, would be a non-polar molecule because the N atoms share their electrons equally; i.e., there is no difference in their electronegativity. For this question you want the EN to be as close to zero as you can get it to be completely non-polar. So I think the answer is between B-C and C-Si and I would pick C-Si as you did.