NO2 Lewis Structure

NO2 Lewis Structure

NO2 (nitrogen dioxide) has one nitrogen atom and two oxygen atoms. In the lewis structure of NO2, there is one double bond and one single bond around the nitrogen atom, with two oxygen atoms attached to it. The oxygen atom with a double bond has two lone pairs, the oxygen atom with a single bond has three lone pairs, and the nitrogen atom has one unpaired electron.

Also, there is a positive (+1) charge on the nitrogen atom, and a negative (-1) charge on the oxygen atom with a single bond.

Steps

Here’s how you can draw the NO2 lewis structure step by step.

Step #1: draw sketch
Step #2: mark lone pairs
Step #3: mark charges
Step #4: minimize charges
Step #5: minimize charges again (if there are)

Let’s break down each step in detail.

#1 Draw Sketch

  • First, determine the total number of valence electrons

In the periodic table, nitrogen lies in group 15, and oxygen lies in group 16.

Hence, nitrogen has five valence electrons and oxygen has six valence electrons.

Since NO2 has one nitrogen atom and two oxygen atoms, so…

Valence electrons of one nitrogen atom = 5 × 1 = 5
Valence electrons of two oxygen atoms = 6 × 2 = 12

And the total valence electrons = 5 + 12 = 17

  • Second, find the total electron pairs

We have a total of 17 valence electrons. And when we divide this value by two, we get the value of total electron pairs.

But 17 can not be divided by two. Hence, there are a total of 8 electron pairs and one unpaired electron.

  • Third, determine the central atom

We have to place the least electronegative atom at the center.

Since nitrogen is less electronegative than oxygen, assume that the central atom is nitrogen.

Therefore, place nitrogen in the center and oxygens on either side.

  • And finally, draw the rough sketch
NO2 Lewis Structure (Step 1)

#2 Mark Lone Pairs

Here, we have 8 electron pairs and one unpaired electron. And two N — O bonds are already marked. So we have to only mark the remaining six electron pairs and one unpaired electron as lone pairs on the sketch.

Also remember that both (nitrogen and oxygen) are the period 2 elements, so they can not keep more than 8 electrons in their last shell.

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are oxygens.

So for each oxygen, there are three lone pairs, and for nitrogen, there is one unpaired electron.

Mark the lone pairs on the sketch as follows:

NO2 Lewis Structure (Step 2)

#3 Mark Charges

Use the following formula to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

For nitrogen atom, formal charge = 5 – 1 – ½ (4) = +2

For each oxygen atom, formal charge = 6 – 6 – ½ (2) = -1

Here, both nitrogen and oxygen atoms have charges, so mark them on the sketch as follows:

NO2 Lewis Structure (Step 3)

The above structure is not a stable lewis structure because both nitrogen and oxygen atoms have charges. Therefore, reduce the charges (as below) by converting lone pairs to bonds.

#4 Minimize Charges

Convert a lone pair of the oxygen atom to make a new N — O bond with the nitrogen atom as follows:

NO2 Lewis Structure (Step 4)

In the above structure, you can see that the central atom (nitrogen) doesn’t form an octet. And there are still charges on the atoms.

But we can not convert a lone pair to a bond because nitrogen can not keep more than 8 electrons in its last shell. So no need to worry about the octet rule here.

The formal charges on atoms are closer to zero. Also, the above structure is more stable than the previous structures. Therefore, this structure is the most stable lewis structure of NO2.

Next: NH3 Lewis Structure

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