## Formal Charge Formula Clarification

904605949
Posts: 20
Joined: Wed Sep 21, 2016 2:58 pm

### Formal Charge Formula Clarification

I'm confused on how the Formal Charge Formula FC=V-(L+S/2) works since I keep getting the lone pair variable (L) and the shared bonds/electrons variable (S) confused when I draw a Lewis Dot Structure because I'm not sure which part of the diagram is the L variable and which part of the diagram would be the S variable in the formula. Also when we do solve for the formal charge does our answer always have to equal to zero in order for the compound to be stable and the correct indication in drawing the compound structure?

Evan Lee 2D
Posts: 18
Joined: Wed Sep 21, 2016 2:58 pm

### Re: Formal Charge Formula Clarification

L is the variable for the lone pair electrons, which are the electrons that you draw as dots on the Lewis Structure. S is the variable for the shared electrons, which is drawn as a dash on the Lewis Structure. Remember that the dash means there are two shared electrons.

Yamilex Velgara 2I
Posts: 21
Joined: Wed Sep 21, 2016 2:59 pm

### Re: Formal Charge Formula Clarification

When solving for formal charge, your compound will only be stable if the formal charge is 0. To determine which of two resonance structures is the most likely, choose the one with the most formal charges of 0 for each atom. Two resonance structures may have an overall formal charge of 0, but the one that is most likely is the one that has more atoms with a formal charge of 0.

Refer to page 82 in the course reader. The structure on the right is more stable because two O atoms have a formal charge of 0.