## Formal CHarge

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

TiffanyL1G
Posts: 61
Joined: Fri Sep 28, 2018 12:22 am

### Formal CHarge

An atom or molecule is the most stable when the formal charge of the lowest ionization energy atom is 0? Or does the whole entire molecule have to equal 0? Is it safe to only check the lowest ionization energy atom is zero (when determining if it is in a stable state) or should I check each individual atom?

Also, I'm still a bit confused about what to do when you check each individual atom's formal charge. Do I add all those charges up, and then does that number become the formal charge of the entire molecule?

Ray Guo 4C
Posts: 90
Joined: Fri Sep 28, 2018 12:15 am

### Re: Formal CHarge

You'd have to check every single atom in the molecule because the molecule is the most stable when each atom in it has a formal charge of 0. You can calculate the formal charge of an atom using the formula [# of valence electrons] - [# of bonded electrons/2] - [# of non-bonding electrons]

taline_n
Posts: 64
Joined: Fri Sep 28, 2018 12:17 am

### Re: Formal CHarge

The formal charge only pertains to each individual atom in a molecule. The molecule as a whole will always remain one indicated charge. For example, SO4^(-2) will always have the charge of -2, although depending on the structure of the molecule, the formal charges for the individual S and O atoms may vary. The structure that contains the formal charges of each specific atom closest to 0 is the most stable.

anishathomas
Posts: 35
Joined: Fri Sep 28, 2018 12:25 am

### Re: Formal CHarge

It would be nice if the formal charges equal zero but sometimes it’s not so it would be the lowest amount for the formal charge.

Courtney Quan 1C
Posts: 60
Joined: Fri Sep 28, 2018 12:26 am
Been upvoted: 2 times

### Re: Formal CHarge

As said above, formal charge is only assigned to an atom and is most stable with it is equal to zero. Make sure that you check the formal charge of each individual atom per each structure to determine which is the most stable. The total charge of a molecule is always one indicated charge and is found by adding the individual charges of the atoms forming the most stable structure, as in the case with SO42- (where the formal charges of sulfur = 0, the 2 double bonded oxygens = 0, and the 2 single bonded oxygens = -1, which gives the ion an overall charge of -2).

Charles Gu 1D
Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

### Re: Formal CHarge

Each atom has its own formal charge. You will need to to check the formal charge of each of them in order to find the stability of the whole molecule.