Nonpolar bonds?

Question

Which of the following has nonpolar bonds?
-H2S
-HCl
-OF2
-Br2
-All are nonpolar

Please explain

Answer 1

All are non polar - I guess it's debatable about HCl

Nonpolar (ie. Covalent) bonds are formed between atoms of high electronegativity. Think of electronegativity as a sort of "greed for electrons"

If you are a sulphur atom and you have 6 electrons in your outer shell, you are looking to gain 2 more electrons to have you (stable) octet (ie 8 electrons in outer shell). If you meet up with a pair of hydrogen atoms - each of them having 1 electron and looking to gain 1 more - you can "grab on" to both of their electrons. However, they are a little electronegative too and grab on to one of yours each so the lot of you are sharing your electrons around.
..
:S--H
/
H

You wind up with 2 paired electrons of your own, and 2 more (one of yours shared with one H) and then a second lot of 2 more (the last of yours shared with the other H)

This argument works better with O (6 electrons, looking to gain 2 more) and F (7 electrons looking to gain 1 more) or Br2 (both Br atoms looking to gain 1 electron and so share).