I’m super excited to teach you the lewis structure of N3- ion in just 6 simple steps.
Infact, I’ve also given the step-by-step images for drawing the lewis dot structure of N3- ion.
So, if you are ready to go with these 6 simple steps, then let’s dive right into it!
Lewis structure of N3- ion (azide ion) contains two single bonds between each Nitrogen (N) atom. The central nitrogen atom does not have lone pairs, while the outer nitrogen atoms have 2 lone pairs.
Let’s draw and understand this lewis dot structure step by step.
(Note: Take a pen and paper with you and try to draw this lewis structure along with me. I am sure you will definitely learn how to draw lewis structure of N3- ion).
6 Steps to Draw the Lewis Structure of N3-
Step #1: Calculate the total number of valence electrons
Here, the given ion is N3- ion (azide ion). In order to draw the lewis structure of N3- ion, first of all you have to find the total number of valence electrons present in the N3- ion.
(Valence electrons are the number of electrons present in the outermost shell of an atom).
So, let’s calculate this first.
Calculation of valence electrons in N3-
- For Nitrogen:
Nitrogen is a group 15 element on the periodic table.
Hence, the valence electrons present in nitrogen is 5 (see below image).
Hence in a N3– ion,
Valence electrons given by each Nitrogen (N) atom = 5
Electron due to -1 charge, 1 more electron is added
So, total number of Valence electrons in N3– ion = 5(3) + 1 = 16
Step #2: Select the center atom
While selecting the atom, you have to put the least electronegative atom at the center.
But here in the N3- ion, all the three atoms are the same. So you can consider any of the atoms as a center atom.
Step #3: Put two electrons between the atoms to represent a chemical bond
Now in the above sketch of N3 molecule, put the two electrons (i.e electron pair) between these three nitrogen atoms to represent a chemical bond between them.
These pair of electrons present between the Nitrogen (N) atoms form a chemical bond, which bonds the nitrogen atoms with each other in an N3 molecule.
Step #4: Complete the octet (or duplet) on outside atom. If the valence electrons are left, then put the valence electrons pair on the central atom
Don’t worry, I’ll explain!
In the Lewis structure of N3, the outer atoms are nitrogen atoms only.
So now, you have to complete the octet on these outer nitrogen atoms (because nitrogen requires 8 electrons to have a complete outer shell).
Now, you can see in the above image that both the nitrogen atoms form an octet.
Also, all the 8 valence electrons of N3- ion (as calculated in step #1) are used in the above structure. So there are no remaining electron pairs.
Hence there is no change in the above sketch of N3.
Let’s move to the next step.
Step #5: Check whether the central atom has octet or not. If it does not have an octet, then move the electron pair from the outer atom to form a double bond or triple bond
In this step, we have to check whether the central atom (i.e central nitrogen) has an octet or not.
In simple words, we have to check whether the central Nitrogen (N) atom has 8 electrons or not.
As you can see from the above image, the central nitrogen atom has only 4 electrons. So it does not fulfill the octet rule.
Now, in order to fulfill the octet of central nitrogen atom, we have to move the electron pair from the outer nitrogen atom to form a double bond.
Still, the octet of central nitrogen atom is not fulfilled as it has only 6 electrons.
So again moving the electron pair from another nitrogen atom, we will get the following structure.
Now you can see from the above image that the central nitrogen atom is having 8 electrons. So it fulfills the octet rule and the nitrogen atom is stable.
Step #6: Final step – Check the stability of lewis structure by calculating the formal charge on each atom
Now, you have come to the final step and here you have to check the formal charge on each nitrogen atom (N).
For that, you need to remember the formula of formal charge;
Formal charge = Valence electrons – Nonbonding electrons – (Bonding electrons)/2
- For central Nitrogen:
Valence electron = 5 (as it is in group 15)
Nonbonding electrons = 0
Bonding electrons = 8
- For outer Nitrogens:
Valence electron = 5 (as it is in group 15)
Nonbonding electrons = 4
Bonding electrons = 4
|Formal charge||=||Valence electrons||–||Nonbonding electrons||–||(Bonding electrons)/2|
Let’s keep these charges on the atoms in the above lewis structure of N3 molecule.
As you can see in the above sketch, there are still +1 and -1 charges on the Nitrogen atoms. The pair of positive and negative charges gets canceled.
So, there is only one -ve charge left on the nitrogen atom, which indicates the -1 formal charge on the N3- ion.
Each electron pair (:) in the lewis dot structure of N3- ion represents the single bond ( | ). So the above lewis dot structure of N3- ion can also be represented as shown below.