Does bond order affect polarity?

1 Answer
Apr 13, 2014

Yes, it does. Here is a quick explanation.

If you have methane (#CH_4#) you would notice that it has 4 covalent bonds. The Lewis structure of methane shows a central atom surrounded by four separate regions of high electron density. Each region consists of a pair of electrons bonding the carbon atom to a hydrogen atom. According to the VSEPR model, these regions of high electron density spread out from the central carbon atom in such a way that they are as far from one another as possible. This is NOT a polar molecule. The angle between any two hydrogen atom will be 109.5°.

But, ammonia (#NH_3#) is a polar molecule. We can predict the shape of the ammonia molecule in exactly the same manner. The Lewis structure of #NH_3# shows a central nitrogen atom surrounded by four separate regions of high electron density. Three of these regions consist of a single pair of electrons forming a covalent bond with a hydrogen atom and the fourth region contains an unshared pair of electrons. The observed bond angle here is 107.3°