What is the Charge on NO2 (Nitrite ion)? And Why?

The Charge of NO2 (Nitrite ion) is 1-.

But the question is how can you find the charge on NO2 (nitrite ion)?

Well there are 2 methods by which you can find the charge of NO2.

Lets dive right into these methods one by one.

You can also refer to the below video from which you will learn to find charge of any ion.

Method 1: By looking at what it is bonded to

The charge of NO2 (Nitrite ion) can be found out by looking at what it is bonded to.

So let’s take some examples of compounds that contain NO₂; like NaNO₂, KNO₂, etc.

Example 1: NaNO₂
In NaNO₂, the NO₂ is bonded to Sodium (Na).
You know that the ionic charge of Na is 1+.
So you can easily say that the charge of NO₂ should be 1-, then only it will get canceled out.
Hence the charge of NO₂ in NaNO₂ is 1-.

Example 2: KNO₂
In KNO₂, the NO₂ is bonded to Potassium (K).
And again, you know that the ionic charge of K is 1+.
So here also you can easily say that the charge of NO₂ should be 1-, then only it will get canceled out.
Hence the charge of NO₂ in KNO₂ is 1-.

As seen from the above examples,
The charge of NO2 is 1-.

In this way, you can easily find the charge of NO2 by looking at what it is bonded to.

Method 2: By calculating the formal charge using lewis structure

In order to calculate the formal charge on NO2 (Nitrite ion), you should know the Lewis dot structure of NO2 (Nitrite ion).

Here is the lewis structure of NO2.

Now using the above lewis structure of NO2, you have to find the formal charge on each atom that is present in the NO2 molecule.

For calculating the formal charge, you need to remember this formula;

Formal charge = Valence electrons – Nonbonding electrons – (Bonding electrons)/2

You can see the bonding and nonbonding electrons of NO2 from the image given below.

So now let’s calculate the formal charge on each individual atom present in NO2.

Formal charge on Nitrogen atom:
Valence electrons = 5 (as it is in group 15 on periodic table) ^[1]
Nonbonding electrons = 2
Bonding electrons = 6

So according to the formula of formal charge, you will get;

Formal charge on Nitrogen = Valence electrons – Nonbonding electrons – (Bonding electrons)/2 = 5 – 2 – (6/2) = 0

So the formal charge on nitrogen atom is 0.

Formal charge on double bonded Oxygen atom:
Valence electron = 6 (as it is in group 16 on periodic table) ^[2]
Nonbonding electrons = 4
Bonding electrons = 4

So according to the formula of formal charge, you will get;

Formal charge on double bonded Oxygen = Valence electrons – Nonbonding electrons – (Bonding electrons)/2 = 6 – 4 – (4/2) = 0

So the formal charge on double bonded oxygen atom is 0.

Formal charge on single bonded Oxygen atom:
Valence electron = 6 (as it is in group 16 on periodic table)
Nonbonding electrons = 6
Bonding electrons = 2

So according to the formula of formal charge, you will get;

Formal charge on single bonded Oxygen = Valence electrons – Nonbonding electrons – (Bonding electrons)/2 = 6 – 6 – (2/2) = 1-

So the formal charge on single bonded oxygen atom is 1-.

Now let’s put all these charges on the lewis dot structure of NO2.

So there is overall 1- charge left on the entire molecule.

This indicates that the NO2 (Nitrite ion) has 1- charge.

I hope you have understood the above calculations of NO2 (Nitrite ion). But for your tests, you don’t need to remember the entire calculations. You should just try to remember that NO2 has 1- charge.

Check out some other related topics for your practice.

Related topics:
Charge on CO (Carbon monoxide)
Charge of Barium (Ba)
Charge of Fluorine (F)
Charge of Lithium (Li)
Charge of Cobalt (Co)