## Formal Charges on Atoms Summed in Ions?

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

Bita Ghanei 1F
Posts: 60
Joined: Thu Feb 28, 2019 12:15 am

### Formal Charges on Atoms Summed in Ions?

If you have an ion with one atom having a +1 formal charge and another atom having a -1 formal charge, do these charges cancel each other out if there are only two atoms in the ion?

connie 2C
Posts: 106
Joined: Thu Jul 11, 2019 12:17 am

### Re: Formal Charges on Atoms Summed in Ions?

can you provide an example? if it's just adding formal charges then yes they do cancel out.

Kelvin Chung 1C
Posts: 50
Joined: Sat Aug 24, 2019 12:15 am

### Re: Formal Charges on Atoms Summed in Ions?

In an ion, generally the formal charges should add up to the charge of the ion. In a molecule, I believe the formal charges should add up to 0.

Jocelyn Thorp 1A
Posts: 103
Joined: Wed Sep 18, 2019 12:20 am

### Re: Formal Charges on Atoms Summed in Ions?

Kelvin Chung 1C wrote:In an ion, generally the formal charges should add up to the charge of the ion. In a molecule, I believe the formal charges should add up to 0.

exactly. for example Na has a formal charge of +1 and Cl has a formal charge of -1. Their combined compound NaCl has a formal charge of zero.

Jordan Ziegler 2J
Posts: 59
Joined: Sat Aug 17, 2019 12:15 am

### Re: Formal Charges on Atoms Summed in Ions?

In covalent bonding with a zero charge, the formal charges will always work out to cancel each other out.

For example, the least stable resonance hybrid of HClO4 has all single bonds. The formal charges on three oxygens are -1 (6 valence - (1 bonding site + 6 lone electrons), and the formal charge on the central chlorine atom is +3 (7 valence electrons - 4 bonding sites). These formal charges will cancel each other out in the big picture of the molecule.

romina_4C
Posts: 100
Joined: Thu Jul 11, 2019 12:17 am

### Re: Formal Charges on Atoms Summed in Ions?

If the molecule does not have a charge associated to it (a charge like $SO_4{}^{-2}$), then the formal charges should cancel out to zero. In the example of the molecule I mentioned the overall formal charges of the molecule should equal -2, since the molecule has a charge of -2.

Manav Govil 1B
Posts: 104
Joined: Sat Sep 07, 2019 12:19 am

### Re: Formal Charges on Atoms Summed in Ions?

Also, the more formal charges there are that equal to zero, the more stable the molecule actually is.