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

I’m super excited to teach you the lewis structure of HCl in just 6 simple steps.

Infact, I’ve also given the step-by-step images for drawing the lewis dot structure of HCl molecule.

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

Lewis structure of HCl (or Hydrogen chloride) contains one single bond between the Hydrogen (H) and Chlorine (Cl) atom. The Chlorine atom has 3 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 HCl).

6 Steps to Draw the Lewis Structure of HCl

Step #1: Calculate the total number of valence electrons

Here, the given molecule is HCl (hydrogen chloride). In order to draw the lewis structure of HCl, first of all you have to find the total number of valence electrons present in the HCl molecule.
(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 HCl

• For Hydrogen: 

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

Hence, the valence electron present in hydrogen is 1 (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 HCl molecule, 

Valence electrons given by Chlorine (Cl) atom = 7
Valence electron given by Hydrogen (H) atom = 1
So, total number of Valence electrons in HCl molecule = 1 + 7 = 8

Step #2: Select the center atom (H is always outside)

While selecting the atom, you have to put the least electronegative atom at the center. 

But here in the HCl molecule, there are only two atoms. So you can consider any of the atoms as a center atom.

So, let’s assume that the chlorine atom is a central atom. (Because hydrogen is always placed outside in any lewis structure.)

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

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

These pair of electrons present between the Chlorine (Cl) and Hydrogen (H) atoms form a chemical bond, which bonds the chlorine and hydrogen atoms with each other in a HCl 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 HCl, the outer atom is hydrogen atom.

So now, you have to check whether this hydrogen atom is forming a duplet or not! (because hydrogen requires only 2 electrons to have a complete outer shell).

You can see in the above image that the hydrogen atom forms a duplet.

Also, only 2 valence electrons of HCl molecule are used in the above structure.

But there are total 8 valence electrons in HCl molecule (as calculated in step #1).

So the number of electrons left to be kept on the atom (i.e chlorine atom) = 8 – 2 = 6.

So let’s keep these six electrons (i.e 3 electron pairs) on the chlorine atom.

Now, let’s move to the next step.

Step #5: Check whether the central atom has octet or not

In this step, we have to check whether the central atom (i.e chlorine) has an octet or not. 

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

As you can see from the above image, the central atom (i.e chlorine), is having 8 electrons. So it fulfills the octet rule and the chlorine 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 chlorine atom (Cl) as well as hydrogen atom (H).

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

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

• For Chlorine:
  Valence electrons = 7 (as it is in group 17)
  Nonbonding electrons = 6
  Bonding electrons = 2
• For Hydrogen:
  Valence electron = 1 (as it is in group 1)
  Nonbonding electrons = 0
  Bonding electrons = 2

Formal charge	=	Valence electrons	–	Nonbonding electrons	–	(Bonding electrons)/2
Cl	=	7	–	6	–	2/2	=	0
H	=	1	–	0	–	2/2	=	0

So you can see above that the formal charges on chlorine as well as hydrogen are “zero”.

Hence, there will not be any change in the above structure and the above lewis structure of HCl is the final stable structure only.

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

Related lewis structures for your practice:
Lewis structure of H2
Lewis structure of N3-
Lewis structure of BH3
Lewis structure of C2H6
Lewis structure of COCl2

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