## Calculating Formal Charge [ENDORSED]

$FC=V-(L+\frac{S}{2})$

Phoebe Hao 1J
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Joined: Fri Sep 25, 2015 3:00 am

### Calculating Formal Charge

Is there ever a time when calculating formal charge that it won't sum to the overall charge of the atom? (Meaning that the way you drew the lewis dot structure is not correct/ ideal, and therefore, there is a better way to draw it?) Or does it always work out?
Also, what can we do from the information that we get from formal charge?
Thanks!

Jamlah Dalie 1K
Posts: 62
Joined: Fri Sep 25, 2015 3:00 am

### Re: Calculating Formal Charge

Well the formal charge of the molecule is always given to us so when we're drawing out the lewis structure we should always be careful to check if the formal charge is correct in the end that way we can determine if we've drawn out the best structure. If the formal charge doesn't check out then you know you've done something wrong. Also when drawing out the structures, you should try to have the central atom be neutral, meaning the formal charge is 0, because that is when the molecule is most stable, and usually this is also the best lewis structure you can draw out.

stacey
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Joined: Wed Sep 30, 2015 3:00 am

### Re: Calculating Formal Charge

The formal charge of every atom always adds up to the overall charge. Generally, when the formal charge of each atom is closer to 0, the structure is more stable.

Esteban Espinoza
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Joined: Fri Jun 17, 2016 11:28 am

### Re: Calculating Formal Charge

When calculating the Formal Charge of a chemical bond, is it safe to assume that S = The number of bonds rather then S/2?

Chem_Mod
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### Re: Calculating Formal Charge  [ENDORSED]

Esteban Esoinoza Lab 1B wrote:When calculating the Formal Charge of a chemical bond, is it safe to assume that S = The number of bonds rather then S/2?

Yes that gives the same answer.

The equation was developed (and defined) with respect to electrons (lone pair and bonding pair electrons).
That is why the wording is what my lecture notes use.