So you have seen the above image by now, right?
Let me explain the above image in short.
N2 lewis structure has two Nitrogen atoms (N) which contain a triple bond between them. There is 1 lone pair on both the Nitrogen atoms (N).
If you haven’t understood anything from the above image of N2 (nitrogen gas) lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of N2.
So let’s move to the steps of drawing the lewis structure of N2.
Steps of drawing N2 lewis structure
Step 1: Find the total valence electrons in N2 molecule
In order to find the total valence electrons in N2 (nitrogen gas) molecule, first of all you should know the valence electrons present in a single nitrogen atom.
(Valence electrons are the electrons that are present in the outermost orbit of any atom.)
Here, I’ll tell you how you can easily find the valence electrons of nitrogen using a periodic table.
Total valence electrons in N2 molecule
→ Valence electrons given by nitrogen atom:
Nitrogen is a group 15 element on the periodic table.  Hence the valence electrons present in nitrogen is 5.
You can see the 5 valence electrons present in the nitrogen atom as shown in the above image.
Total valence electrons in N2 molecule = 5(2) = 10.
Step 2: Select the central atom
For selecting the center atom, you have to remember that the atom which is less electronegative remains at the center.
Now here the given molecule is N2 (nitrogen gas). Both the atoms are same, so you can select any of the atoms as a center atom.
Let’s assume the right side nitrogen as a central atom.
Step 3: Connect each atoms by putting an electron pair between them
Now in the N2 molecule, you have to put the electron pairs between both the nitrogen atoms (N).
This indicates that both the nitrogen (N) atoms are chemically bonded with each other in a N2 molecule.
Step 4: Make the outer atoms stable. Place the remaining valence electrons pair on the central atom.
Now in this step, you have to check the stability of the outer atom.
Here in the sketch of N2 molecule, we have assumed the right side nitrogen atom as a center atom. So the left side nitrogen is the outer atom.
Hence you have to make the left side nitrogen stable.
You can see in the below image that the left side nitrogen atom is forming an octet and hence it is stable.
Also, in step 1 we have calculated the total number of valence electrons present in the N2 molecule.
The N2 molecule has a total 10 valence electrons and out of these, only 8 valence electrons are used in the above sketch.
So the number of electrons which are left = 10 – 8 = 2.
You have to put these 2 electrons on the right side nitrogen atom in the above sketch of N2 molecule.
Now let’s proceed to the next step.
Step 5: Check the octet on the central atom. If it does not have octet, then shift the lone pair to form a double bond or triple bond.
In this step, you have to check whether the central (i.e right side) nitrogen atom (N) is stable or not.
In order to check the stability of this nitrogen (N) atom, we have to check whether it is forming an octet or not.
Unfortunately, this nitrogen atom is not forming an octet here. Nitrogen has only 4 electrons and it is unstable.
Now to make this nitrogen atom stable, you have to shift the electron pair from the left nitrogen atom.
But after shifting one electron pair, the right side nitrogen atom is still not forming an octet as it has only 6 electrons.
So again we have to shift one more electron pair from the left side nitrogen atom.
After shifting this electron pair, the right side nitrogen atom will get 2 more electrons and thus its total electrons will become 8.
You can see from the above picture that the right side nitrogen atom is forming an octet.
And hence this nitrogen atom is stable.
Now let’s proceed to the final step to check whether the lewis structure of N2 is stable or not.
Step 6: Check the stability of lewis structure
Now you have come to the final step in which you have to check the stability of lewis structure of N2.
The stability of lewis structure can be checked by using a concept of formal charge.
In short, now you have to find the formal charge on both the nitrogen (N) atoms present in the N2 molecule.
For calculating the formal charge, you have to use the following formula;
Formal charge = Valence electrons – (Bonding electrons)/2 – Nonbonding electrons
You can see the number of bonding electrons and nonbonding electrons in the image given below.
For Nitrogen (N) atom:
Valence electrons = 5 (because nitrogen is in group 15)
Bonding electrons = 6
Nonbonding electrons = 2
|Formal charge||=||Valence electrons||–||(Bonding electrons)/2||–||Nonbonding electrons|
From the above calculations of formal charge, you can see that both the nitrogen (N) atoms have a “zero” formal charge.
This indicates that the above lewis structure of N2 is stable and there is no further change in the above structure of N2.
In the above lewis dot structure of N2, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of N2.
I hope you have completely understood all the above steps.
For more practice and better understanding, you can try other lewis structures listed below.
Try (or at least See) these lewis structures for better understanding: