## Finding the Formal Charge

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

Kathleen Vidanes 1E
Posts: 62
Joined: Fri Sep 29, 2017 7:07 am

### Finding the Formal Charge

How do we know when to stop changing the numbers within the formula for formal charge in order to obtain the best representation of a certain molecule? For example, SO4^2-

Lily Sperling 1E
Posts: 49
Joined: Tue Oct 10, 2017 7:14 am

### Re: Finding the Formal Charge

In the case of SO4^2-, the total charge should add up to 2-. Since "S" has the lowest ionization energy, it is the central atom and should therefore have a formal charge of zero, which would leave two of the oxygens with a formal charge of 1-. Oxygen is much more likely to have a negative tendency so we would write the correct lewis structure with two double bonds to make this happen. Lowest formal charge and octet followed is ideal.

605011646
Posts: 14
Joined: Fri Sep 29, 2017 7:07 am

### Re: Finding the Formal Charge

why is it that the central atom in a molecule usually doesn't hold a formal charge well?

Jacquelyn Hill 1
Posts: 41
Joined: Sat Jul 22, 2017 3:01 am

### Re: Finding the Formal Charge

If a central atom has a formal charge, then the overall molecule will have an unbalanced charge and be more unstable than if it did not have a formal charge.