Formal Charge (FC) = the charge an atom would have if all bonding pairs were shared equally (polar bonds don't exist in this model).

To assign Formal Charges:

  1. Draw a correct Lewis Structure.

  2. Assign both electrons of a lone pair to its associated atom.

  3. Divide all bonding pairs, giving one electron of each pair to each atom in the bond.

  4. Calculate FC = # electrons on the unbonded (elemental) atom - # electrons assigned to the bonded atom.



















Clark's Method (abbreviated) for determining bonding in covalent Lewis Structures:











© R A Paselk

Last modified 3 April 2015