Formal Charge

Formal charge is the process of assigning electrons to a particular element in a compound (or ion).

To determine formal charge, you apply the following processes:

  1. Assign half of all shared electron (those present in covalent bonds) to each of the elements that share those electrons.
  2. Assign all lone pairs (or single electrons) on an atom to that particular atom.
  3. Add together assigned shared electrons (half of those in any covalent bonds) to the number of electrons existing as lone pairs or single electrons.
  4. Compare the total number of assigned electrons (from step #3 above) to the Group Number (Valence Number) of that element in the Periodic Table.

Now, to get Formal Charge, you must achieve one of the following: