a level chemistry aqa

bonding if your where ask to to predict a shape molecule based on its bonding pairs and lone pairs how would you word it. (6mark) what if there two lone pairs. can you say lone pairs repel more than bonding pairs so electron pair repel as far as possible causing the bond angle to decrease and would you have to write the shape and number of bonding pairs etc.

Reply 1

A_grant05

I don't have your question, so it's a little hard to answer exact to your question.

If 2 bonding pairs, 0 lone pairs, the shape would be linear (180 degrees) as the bonding pairs want to repel each other as much as possible.
If 3 bonding pairs, 0 lone pairs, the shape is trigonal planar (120 degrees) as the bonding want to repel each other as much as possible.
If 2 bonding pairs, 1 lone pair, the shape is bent (~117.5 degrees). This is because the bonding pairs repel other electron pairs slightly more than a regular bonding pair.

These are probably acceptable answers, not that I've ever seen a 6 mark question on bond angles. If you are able to send me a copy of the exact question you are answering I can give it a go