Question

Calculate the formal charge on the indicated atom in each of the following molecules or ions. Some molecules may have more than one possible resonance structure, each resulting in a different possible formal charge on the indicated atom. In such cases, supply both unique formal charge values separated by commas.Part Cnitrogen in NO2If there is more than one answer, separate them by commas.

Answer 1

Answer:

Formal charge for the first resonance structure of NO₂; first Oxygen = 0, N = +1, second Oxygen = -1

Formal charge for the second resonance structure of NO₂; first Oxygen = -1, N = +1, second Oxygen = 0

Explanation:

The formal charge of an atom in a molecule is the assumed charge the atom would have if the electrons in the bonds are redistributed evenly between the atoms.

Formal charge = valence electrons - (non-bonding electrons) - (bonding electrons / 2).

For NO₂ molecule, the formal charges for the atoms are as follows;

First Oxygen atom = 6 - 4 - 4/2 = 0

For Nitrogen = 5 - 1 - 6/2 = +1

For the second Oxygen atom = 6 - 6 - 2/2 = -1.

Overall charge = 0 + (+1) + (-1) = 0

For the second resonance structure,

First Oxygen atom = 6 - 6 - 2/2 = -1

For Nitrogen = 5 - 1 - 6/2 = +1

For the second Oxygen atom =  6 - 4 - 4/2 = 0

Overall charge = (-1) + (+1) + (0) = 0

Note: Where resonance structures for atoms or ions exist, the formal charges of each of the respective atoms or ions are calculated according.

Answer 2

Answer:

The formal charge on nitrogen in $NO_2$ is 0

Explanation:

Formal charge is the charge that is given to an atom in a molecule by assuming that the shared electrons between the two bonded atoms are equally shared between them.

It could be calculated as follows

formal charge = $N_{valence}-N_{non-bond}-\frac{N_{bond}}{2}$

where

$N_{valence}=$ Number of valence electrons

$N_{non-bond} =$ Number of non-bonding electrons

$N_{bond} =$ Number of bonding electrons

The number of valence electrons on nitrogen is 5.

The number of non-bonding and bonding electrons are 2 and 6 respectively. Substituting into the equation above, we get

$FC=5-2-\frac{6}{2} =0$

Therefore the formal charge on nitrogen in $NO_2$ is 0