Some molecules w/ non polar bonds like C-S and C-I when exposed to a highly polar environment may assume polarity
-Due to vacant d orbitals of S (i don't get this. So if it has a lot of vacant orbitals it will be polar?)
-big atomic radius of I (please explain this to me)
S and I are included in EN how come it's non polar?
3 answers
Large molecules, such as I, can be induced to be polar when a highly EN element (such as F or Cl) come close. Smaller molecules don't do that because the electron field is so much closer to the nucleus. The large size of the I atom, however, makes the outer electrons less susceptible to the pull of the protons in the nucleus and more susceptible to a highly polar group approaching from the outside. So the electron field of the I atom can be distorted by a highly EN approaching group.
thanks.. but what does it mean to be induced?
In this case inducing simply means that the highly EN group that gets close to the electronic cloud of the non-polar molecule distorts the cloud to make the molecule polar. That is, the EN group induces a polarity that is not there on its own.