So you have seen the above image by now, right?
Let me explain the above image in short.
C2H3Cl lewis structure has a double bond between the Carbon-Carbon atoms and a single bond between the Carbon-Hydrogen atoms and Carbon-Chlorine atoms. There are 3 lone pairs on Chlorine atom (Cl).
If you haven’t understood anything from the above image of C2H3Cl lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of C2H3Cl.
So let’s move to the steps of drawing the lewis structure of C2H3Cl.
Steps of drawing C2H3Cl lewis structure
Step 1: Find the total valence electrons in C2H3Cl molecule
In order to find the total valence electrons in a C2H3Cl molecule, first of all you should know the valence electrons present in carbon atom, hydrogen atom as well as chlorine 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 carbon, hydrogen as well as chlorine using a periodic table.
Total valence electrons in C2H3Cl molecule
→ Valence electrons given by carbon atom:
Carbon is group 14 element on the periodic table. [1] Hence the valence electrons present in carbon is 4.
You can see the 4 valence electrons present in the carbon atom as shown in the above image.
→ Valence electrons given by hydrogen atom:
Hydrogen is group 1 element on the periodic table. [2] Hence the valence electron present in hydrogen is 1.
You can see that only 1 valence electron is present in the hydrogen atom as shown in the above image.
→ Valence electrons given by chlorine atom:
Chlorine is group 17 element on the periodic table. [3] Hence the valence electrons present in chlorine is 7.
You can see the 7 valence electrons present in the chlorine atom as shown in the above image.
Hence,
Total valence electrons in C2H3Cl molecule = valence electrons given by 2 carbon atoms + valence electrons given by 3 hydrogen atoms + valence electrons given by 1 chlorine atom = 4(2) + 1(3) + 7 = 18.
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.
(Remember: If hydrogen is present in the given molecule, then always put hydrogen outside.)
Now here the given molecule is C2H3Cl and it contains carbon atom (C), hydrogen atoms (H) and chlorine atom (Cl).
So as per the rule we have to keep hydrogen outside.
Now, you can see the electronegativity values of carbon atom (C) and chlorine atom (Cl) in the above periodic table.
If we compare the electronegativity values of carbon (C) and chlorine (Cl) then the carbon atom is less electronegative.
So here the carbon atom (C) is the center atom and the chlorine atom (Cl) is the outside atom.
Step 3: Connect each atoms by putting an electron pair between them
Now in the C2H3Cl molecule, you have to put the electron pairs between the carbon (C) & chlorine (Cl) atom and between the carbon (C) & hydrogen (H) atoms.
This indicates that these atoms are chemically bonded with each other in a C2H3Cl molecule.
Step 4: Make the outer atoms stable
Now in this step, you have to check the stability of the outer atoms.
Here in the sketch of C2H3Cl molecule, you can see that the outer atoms are hydrogen atoms and chlorine atom.
These hydrogen atoms and chlorine atom are forming a duplet and octet respectively and hence they are stable.
Also, in step 1 we have calculated the total number of valence electrons present in the C2H3Cl molecule.
The C2H3Cl molecule has a total 18 valence electrons and out of these, only 16 valence electrons are used in the above sketch.
So the number of electrons which are left = 18 – 16 = 2.
You have to put these 2 electrons on any of the carbon atoms in the above sketch of C2H3Cl 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 carbon atoms (C) are stable or not.
In order to check the stability of the central carbon (C) atoms, we have to check whether they are forming an octet or not.
Unfortunately, one of the carbon atoms is not forming an octet here.
Now to make this carbon atom stable, you have to convert the lone pair into a double bond so that the carbon atom can have 8 electrons (i.e octet).
After converting this electron pair into a double bond, the central carbon atom will get 2 more electrons and thus its total electrons will become 8.
You can see from the above picture that both the carbon atoms are forming an octet.
And hence these carbon atoms are stable.
Now let’s proceed to the final step to check whether the lewis structure of C2H3Cl 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 C2H3Cl.
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 carbon (C) atom, hydrogen (H) atoms as well as chlorine (Cl) atom present in the C2H3Cl 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 for each atom of C2H3Cl molecule in the image given below.
For Carbon (C) atom:
Valence electrons = 4 (because carbon is in group 14)
Bonding electrons = 8
Nonbonding electrons = 0
For Hydrogen (H) atom:
Valence electron = 1 (because hydrogen is in group 1)
Bonding electrons = 2
Nonbonding electrons = 0
For Chlorine (Cl) atom:
Valence electrons = 7 (because chlorine is in group 17)
Bonding electrons = 2
Nonbonding electrons = 6
Formal charge | = | Valence electrons | – | (Bonding electrons)/2 | – | Nonbonding electrons | ||
C | = | 4 | – | 8/2 | – | 0 | = | 0 |
H | = | 1 | – | 2/2 | – | 0 | = | 0 |
Cl | = | 7 | – | 2/2 | – | 6 | = | 0 |
From the above calculations of formal charge, you can see that the carbon (C) atom, hydrogen (H) atom as well as chlorine (Cl) atom have a “zero” formal charge.
This indicates that the above lewis structure of C2H3Cl is stable and there is no further change in the above structure of C2H3Cl.
In the above lewis dot structure of C2H3Cl, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of C2H3Cl.
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:
SiBr4 Lewis Structure | SeO3 Lewis Structure |
CHF3 Lewis Structure | BrO4- Lewis Structure |
NO2F Lewis Structure | XeOF4 Lewis Structure |
Jay is an educator and has helped more than 100,000 students in their studies by providing simple and easy explanations on different science-related topics. He is a founder of Pediabay and is passionate about helping students through his easily digestible explanations.
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