Lewis structure of NO

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The Lewis structure of NO contains a double bond between the nitrogen atom and oxygen atom. The nitrogen atom has one lone pair and one unpaired electron, and the oxygen atom has two lone pairs.

Steps

By using the following steps, you can easily draw the Lewis structure of NO:

#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Complete octet on central atom
#5 Calculate formal charge and check stability

Let’s one by one discuss each step in detail.

#1 Draw skeleton

In this step, first calculate the total number of valence electrons. And then, decide the central atom.

• Let’s calculate the total number of valence electrons

We know that… nitrogen is a group 15 element and oxygen is a group 16 element. Hence, nitrogen has five valence electrons and oxygen has six valence electrons.

Now NO has one nitrogen atom and one oxygen atom.

So the total number of valence electrons = valence electrons of nitrogen atom + valence electrons of oxygen atom

Therefore, the total number of valence electrons = 5 + 6 = 11

• Now decide the central atom

The atom with the least electronegative value is placed at the center. By looking at the periodic table, we get the electronegativity values for nitrogen and oxygen as follows:

Electronegativity value of nitrogen = 3.04
Electronegativity value of oxygen = 3.44

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

So now, put nitrogen and oxygen next to each other. And draw the rough skeleton structure for the Lewis structure of NO something like this:

Also read: How to draw Lewis structure of NF₃ (4 steps)

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond as follows:

#3 Mark lone pairs

As calculated earlier, we have a total of 11 valence electrons. And in the above structure, we have already used two valence electrons. Hence, nine valence electrons are remaining.

Two valence electrons represent one lone pair. So eight valence electrons = four lone pairs. Also, we have one unpaired electron.

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

Also, make sure that you start marking these lone pairs on outside atoms first. And then, on the central atom.

The outside atom is oxygen, so oxygen will get three lone pairs. And the central atom (nitrogen) will get one lone pair and one unpaired electron.

So the Lewis structure of NO looks something like this:

In the above structure, you can see that the octet is completed on the outside atom. But, the central atom (nitrogen) doesn’t form an octet.

So in the next step, we have to complete the octet on the central atom.

Also read: How to draw Lewis structure of PCl₃ (4 steps)

#4 Complete octet on central atom

Remember that nitrogen is a period 2 element, so it can not keep more than 8 electrons in its last shell.

Now nitrogen already has five valence electrons. Hence, nitrogen needs three more valence electrons to complete its octet.

So convert one lone pair from the oxygen atom to make a new bond with the nitrogen atom. And then, the Lewis structure of NO looks something like this:

In the above structure, you can see that the octet is completed only on the outside atom, and not on the central atom (nitrogen).

But as mentioned above… nitrogen is a period 2 element, so it can not keep more than 8 valence electrons in its last shell.

Therefore, we can not convert a lone pair of the oxygen atom to make a new bond with the nitrogen atom.

Now one last thing we need to do is, calculate the formal charge and check the stability of the above structure.

Also read: How to draw Lewis structure of SF₆ (4 steps)

#5 Calculate formal charge and check stability

The following formula is used to calculate the formal charges on atoms:

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

Collect the data from the above structure and then, write it down below as follows:

• For nitrogen atom

Valence electrons = 5
Nonbonding electrons = 3
Bonding electrons = 4

Formal charge = 5 – 3 – ½ (4) = 0

• For oxygen atom

Valence electrons = 6
Nonbonding electrons = 4
Bonding electrons = 4

Formal charge = 6 – 4 – ½ (4) = 0

Mention the formal charges of atoms on the structure. So the Lewis structure of NO looks something like this:

In the above structure, you can see that the formal charges of both (nitrogen and oxygen) are zero. Therefore, this is the stable Lewis structure of NO.

And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.

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Related

• Lewis structure of NF₃
• Lewis structure of PCl₃
• Lewis structure of SF₆
• Lewis structure of CH₃OH
• Lewis structure of PH₃

External links

• NO (Nitric Oxide) Lewis Structure and Resonance Structures – Chemistry School
• How can I draw the Lewis structure for NO? – Socratic
• NO Lewis Structure in 5 Steps (With Images) – Pediabay
• NO molecular geometry, lewis structure, bond angle, hybridization – Topblogtenz
• Why is it difficult to construct a Lewis structure for NO? – Quora
• NO Lewis Structure: Drawings, Hybridization, Shape, Charges,Pairs and detailed fact – Lambda Geeks
• NO Lewis Structure – The Geoexchange
• NO Lewis Structure, Geometry – Kemicalinfo
• NO Lewis Structure, Molecular Geometry, Hybridization, and MO Diagram – Techiescientist
• Lewis structure of nitric oxide – Chemistry Stack Exchange
• Lewis Dot of Nitrogen Monoxide NO – Kent’s Chemistry
• Draw A Lewis Structure For NO – Chegg