In the next portion of this file you will be looking at structures of oxides and oxoanions.

For a molecule the number of electrons available for bonding is the sum of the valence electrons on its atoms. For an ion the charge must also be taken into account. If the overall charge is

• negative add electrons
  
• positive subtract electrons

For OH^–

Group 16 O(6 × 1)	6 electrons
H (1 × 1)	1 electron
one negative charge	+ 1 electron
total electrons available	8 electrons

For NH₄⁺

Group 15 N(5 × 1)	5 electrons
4H (4 × 1)	4 electron
one positive charge	-1 electron
total electrons available	8 electrons