### How to figure out formal charge?

Posted:

**Sat Jul 16, 2016 5:10 pm**How is formal charge determined?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=33&t=15164

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Posted: **Sat Jul 16, 2016 5:10 pm**

How is formal charge determined?

Posted: **Sun Jul 17, 2016 2:33 pm**

Formal charge in a lewis structure is determined by the formula:

FC = # valence electrons of atom - [lone pair electrons + 1/2*(bonding electrons)]

FC = # valence electrons of atom - [lone pair electrons + 1/2*(bonding electrons)]

Posted: **Fri Oct 21, 2016 9:19 am**

When figuring out a formal charge do we count the individual electrons that are shared or the pairs of electrons that are shared or lone?

Posted: **Thu Oct 27, 2016 2:39 am**

For determining formal charge, it is the number of valance electrons minus the amount of lone electrons and the number of electrons in bonds divided by two. Thus the FC = V - ( L + S/2). A easier way of thinking of the problem in terms of the shared electron is to just consider the number of bonds it has rather than number of electrons in bond divided by two.

Posted: **Thu Oct 27, 2016 6:49 am**

When calculating formal charge it is easiest just to take the number of valence electrons and subtract the number of bonds (same thing as the number of bonded electrons/2) and subtract the number of lone pair electrons. The resulting number is your formal charge. Do this for each of the atoms of your molecule and then add up all the formal charges to give you the total charge of your atom.

Posted: **Sat Oct 28, 2017 4:27 pm**

Formal charge is found by the formula FC= V - (L+(s/2)) where v is the amount of valence electrons of the atom, L is the amount of lone pair electrons, and s/2 is the amount of bonds shared, which can be figured out by divided the electrons shared by 2.

Posted: **Tue Oct 31, 2017 11:20 am**

Also make sure that you memorize the equation or know the concept behind calculating formal charge, because Dr. Lavelle said that he won't provide the equation on the reference sheet!!