Lewis Structure of NCl2- (With 6 Simple Steps to Draw!)

Ready to learn how to draw the lewis structure of NCl2- ion?

Awesome!

Here, I have explained 6 simple steps to draw the lewis dot structure of NCl2- ion (along with images).

So, if you are ready to go with these 6 simple steps, then let’s dive right into it!

Lewis structure of NCl2- ion contains a single bond between the Nitrogen (N) atom and Chlorine (Cl) atoms. The Nitrogen atom (N) is at the center and it is surrounded by 2 Chlorine atoms (Cl). The Nitrogen atom has 2 lone pairs, and both the Chlorine atom has 3 lone pairs. The Nitrogen atom has -1 formal charge.

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 NCl2- ion).

6 Steps to Draw the Lewis Structure of NCl2- ion

Step #1: Calculate the total number of valence electrons

Here, the given ion is NCl2- ion. In order to draw the lewis structure of NCl2- ion, first of all you have to find the total number of valence electrons present in the NCl2- 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 NCl2- ion

• For Nitrogen:

Nitrogen is a group 15 element on the periodic table. ^[1]

Hence, the valence electrons present in nitrogen is 5 (see below image).

• For Chlorine:

Chlorine is a group 17 element on the periodic table. ^[2]

Hence, the valence electron present in chlorine is 7 (see below image).

Hence in a NCl2- ion, 

Valence electrons given by Nitrogen (N) atom = 5
Valence electrons given by each Chlorine (Cl) atom = 7
Electron due to -1 charge, 1 more electron is added
So, total number of Valence electrons in NCl2- ion = 5 + 7(2) + 1 = 20

Step #2: Select the center atom

While selecting the atom, always put the least electronegative atom at the center. 

(Remember: Fluorine is the most electronegative element on the periodic table and the electronegativity decreases as we move right to left in the periodic table as well as top to bottom in the periodic table). ^[3]

Here in the NCl2 molecule, if we compare the nitrogen atom (N) and chlorine atom (Cl), then the nitrogen is less electronegative than chlorine.

So, nitrogen should be placed in the center and the remaining 2 chlorine atoms will surround it.

Step #3: Put two electrons between the atoms to represent a chemical bond

Now in the above sketch of NCl2 molecule, put the two electrons (i.e electron pair) between each nitrogen atom and chlorine atom to represent a chemical bond between them.

These pairs of electrons present between the Nitrogen (N) and Chlorine (Cl) atoms form a chemical bond, which bonds the nitrogen and chlorine atoms with each other in a NCl2 molecule.

Step #4: Complete the octet (or duplet) on outside atoms. 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 NCl2, the outer atoms are chlorine atoms.

So now, you have to complete the octet on these chlorine atoms (because chlorine requires 8 electrons to have a complete outer shell).

Now, you can see in the above image that all the chlorine atoms form an octet.

Also, only 16 valence electrons of NCl2 molecule are used in the above structure.

But there are total 20 valence electrons in NCl2 molecule (as calculated in step #1).

So the number of electrons left to be kept on the central atom = 20 – 16 = 4.

So let’s keep these four electrons (i.e 2 electron pairs) on the central atom.

Now, 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 nitrogen) has an octet or not. 

In simple words, we have to check whether the central Nitrogen (N) atom is having 8 electrons or not.

As you can see from the above image, the central atom (i.e nitrogen), has 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 nitrogen atom (N) as well as each chlorine atom (Cl).

For that, you need to remember the formula of formal charge;

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

• For Nitrogen:
  Valence electron = 5 (as it is in group 15)
  Nonbonding electrons = 4
  Bonding electrons = 4
• For Chlorine:
  Valence electron = 7 (as it is in group 17)
  Nonbonding electrons = 6
  Bonding electrons = 2

Formal charge	=	Valence electrons	–	Nonbonding electrons	–	(Bonding electrons)/2
N	=	5	–	4	–	4/2	=	-1
Cl	=	7	–	6	–	2/2	=	0

Let’s keep these charges on the atoms in the above lewis structure of NCl2- ion.

As you can see in the above sketch, there is one -ve charge on the nitrogen atom, which indicates the -1 formal charge on the NCl2 molecule.

Hence, the above lewis structure of NCl2- ion is the stable lewis structure.

Each electron pair (:) in the lewis dot structure of NCl2- ion represents the single bond ( | ). So the above lewis dot structure of NCl2- ion can also be represented as shown below.

Related lewis structures for your practice:
Lewis Structure of AsCl5
Lewis Structure of COBr2
Lewis Structure of GeF4
Lewis Structure of Cl2O2
Lewis Structure of XeI2 

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