Lewis structure of HCl

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The Lewis structure of HCl contains a single bond between the hydrogen atom and chlorine atom. There are three lone pairs on the chlorine atom, and the hydrogen atom does not have any lone pair.

Steps

By using the following steps, you can easily draw the Lewis structure of HCl:

#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Calculate formal charge and check stability (if octet is already completed on central atom)

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… hydrogen is a group 1 element and chlorine is a group 17 element. Hence, hydrogen has one valence electron and chlorine has seven valence electrons.

Now HCl has one hydrogen atom and one chlorine atom.

So the total number of valence electrons = valence electrons of hydrogen atom + valence electrons of chlorine atom

Therefore, the total number of valence electrons = 1 + 7 = 8

• Now decide the central atom

We can not assume hydrogen as the central atom, because the central atom is bonded with at least two other atoms. And hydrogen has only one electron in its last shell, so it can not make more than one bond.

Hence, assume that chlorine is the central atom.

So now, put hydrogen and chlorine next to each other. And draw the rough skeleton structure for the Lewis structure of HCl something like this:

Also read: How to draw Lewis structure of ClO₂^– (5 steps)

#2 Show chemical bond

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

Also read: How to draw Lewis structure of H₂O₂ (4 steps)

#3 Mark lone pairs

As calculated earlier, we have a total of 8 valence electrons. And in the above structure, we have already used two valence electrons. Hence, six valence electrons are remaining.

Two valence electrons represent one lone pair. So six valence electrons = three lone pairs.

Note that hydrogen is a period 1 element, so it can not keep more than 2 electrons in its last shell. And chlorine is a period 3 element, so it can keep more than 8 electrons in its 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 hydrogen. But hydrogen can not keep more than 2 electrons in its last shell. Hence, don’t mark the lone pairs on hydrogen.

So the central atom (chlorine) will get three lone pairs.

Now draw the Lewis structure of HCl something like this:

In the above structure, you can see that the octet is completed on the central atom (chlorine), and also on the outside atom. Therefore, the octet rule is satisfied.

After completing the octet, 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 ClO₃^– (5 steps)

#4 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 hydrogen atom

Valence electrons = 1
Nonbonding electrons = 0
Bonding electrons = 2

Formal charge = 1 – 0 – ½ (2) = 0

• For chlorine atom

Valence electrons = 7
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 7 – 6 – ½ (2) = 0

Mention the formal charges of atoms on the structure. So the Lewis structure of HCl looks something like this:

In the above structure, you can see that the formal charges of both (hydrogen and chlorine) are zero. Therefore, this is the stable Lewis structure of HCl.

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

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Related

• Lewis structure of ClO₂^–
• Lewis structure of H₂O₂
• Lewis structure of ClO₃^–
• Lewis structure of CH₂Cl₂
• Lewis structure of PCl₅

External links

• Hydrogen Chloride (HCl) Lewis Structure – Chemistry School
• Drawing the Lewis Structure for HCl (Hydrochloric Acid) – The University of Maryland
• HCl Lewis Structure, Molecular Geometry, and Hybridization – Techiescientist
• What is the Lewis electron-dot structure for a molecule of hydrogen chloride? – Socratic
• HCl Lewis Structure in 6 Steps (With Images) – Pediabay
• Draw the Lewis structure for HCl – Homework.Study.com
• How to draw HCl Lewis Structure? – Science Education and Tutorials
• HCL Lewis Dot Structure (Hydrogen Chloride) – Pinterest
• HCl Acid (Hydrochloric acid) – Structure, Properties & Uses – Turito
• Lewis Dot Structure for HCl – The Geoexchange
• hydrogen chloride HCl molecule Lewis dot & cross electronic diagram covalent bonds ball & stick space filling 3D models boiling point melting point Doc Brown’s chemistry revision notes – Doc Brown’s Chemistry
• how does the written Lewis structure for potassium chloride differ from that of hydrogen chloride? – Studocu
• The covalent bond in HCl and the Lewis model – Chemistry Stack Exchange