Lone pairs of electrons

  • 0 votes

Can some one tell me how you work out how many lone pairs are in a molecule?

In questions it asks you to include lone pairs when drawing the shap of molecules. I just can't work it out!

Thanks :)

Posted Thu 3rd January, 2013 @ 19:34 by AmyAmy123

2 Answers

  • 1 vote

Well you know that theres going to be 8 for a full shell. So deduce how many bonding pairs there are and then take those away from 8 and you're left with the remaining lone pairs of electrons. Eg NH3 has 3 bonding pairs with 6 electrons so Nitrogen has 2 electrons (8-6=2)(1 lone pair). In Water H20, there are 2 bonding pairs with 4 electrons so Oxygen will have 4 electrons (8-4=4) (2 lone pairs).

Answered Thu 3rd January, 2013 @ 20:16 by Sakshat
  • 0 votes

Thankyou very much!

Answered Sat 5th January, 2013 @ 21:08 by AmyAmy123