C2H2Cl2 Lewis structure is made up of two carbon atoms, two hydrogens, and two chlorine atoms. Both carbon atoms are kept at the central position and other atoms are at the surrounding position in lewis’s structure. The lewis structure of C2H2Cl2 contains one double bond(C=C) and four single bonds.
The drawing process of the C2H2Cl2 lewis structure is easy and simple. Let’s see how to do it.
Follow some steps for drawing the Lewis structure for C2H2Cl2
1. Count total valence electron in C2H2Cl2
In the very first step, we will count the total valence electron in the C2H2Cl2 molecule. To calculate the valence electron, look at the periodic group of the individual atoms – carbon, hydrogen, and chlorine.
The chlorine atom belongs to the periodic group 7A or 17th in the periodic table, hence, the valence electron for chlorine is 7.
The carbon atom is situated in the 14 or 4A periodic group, hence, its valence electron is 4. The hydrogen atom has only one valence electron.
∴ Total number of valence electrons available for the C2H2Cl2 Lewis structure = 4(2) + 1(2) + 7(2) = 24 valence electrons [∴ C2H2Cl2 molecule has two carbon, two hydrogen, and two chlorine atoms]
2. Find the least electronegative atom and place it at center
Now we will find the least electronegative atom in the C2H2Cl2 compound, after that, we will place it at the center in the lewis diagram and the rest atoms will be spread around it.
The electronegativity value of the carbon atom is 2.55, for a chlorine atom, it is 3.16.
“Hydrogen atoms always go on the outside of a Lewis Structure”.
Hence, the carbon atom is the least electronegative atom in the C2H2Cl2 compound, therefore, we will put both carbon atoms at a central position and (chlorine and hydrogen atom) at the respective position as shown in the figure.
3. Connect outer atoms to central atom with a single bond
In this step, we simply connect each outer atom(chlorine and hydrogen) to the central atom (carbon) with the help of a single bond. Also, we will join both carbon atoms with a single bond as well.
Now count the valence electron used in the above structure. A single bond means two electrons, in the above structure, five single bonds are used.
Therefore, (5 single bonds × 2) = 10 valence electrons are used in the above structure from the total of 24 valence electrons available for drawing the lewis structure of C2H2Cl2.
∴ (24 – 10) = 14 valence electrons
So, we are left with 14 valence electrons more.
4. Place remaining electrons on outer atoms and complete their octet
In this step, we will put the remaining valence electron on the outer atom first for completing their octet. In a C2H2Cl2 molecule, the outer atom is hydrogen and chlorine.
⇒ Hydrogen atoms only need two valence electrons to fulfill the outer shell.
⇒ A chlorine atom needs 8 electrons to complete the outer shell.
As you see in the above figure, we have placed the 6 electrons represented as dots around both chlorine atoms.
∴ Chlorine atoms completed their octet since they have 8 electrons(6 electrons represented as dots + 2 electrons in a single bond).
∴ Hydrogen atoms already completed their octet since they are joined with one single bond means 2 electrons and remember, hydrogen only needs 2 electrons to have a full outer shell.
Now once again count the total valence electron in the above structure.
(5 single bond × 2 electrons + 12 electrons represented as dots) = 22 valence electrons are used in the above structure.
Remember, we had a total of 24 valence electrons available for drawing the lewis structure of C2H2Cl2, and in the above structure, we used 22 valence electrons.
So, we are still left with 2 valence electrons.
5. Complete the octet of the central atom
We know, the carbon atom is the central atom, and it requires a total of 8 electrons to have a full outer shell. We have 2 remaining valence electrons, so, just put these two valence electrons on the carbon atom.
So, we used all the valence electrons that are available for the lewis structure of C2H2Cl2. And by looking at the above structure, we see, the right side carbon atom has 8 electrons(3 single bonds means 6 electrons + 2 electrons represented as dots).
But the left side carbon has only 6 electrons(3 single bonds) which means, it shorts 2 electrons.
For overcoming this problem, move the 2 valence electrons of right side carbon atom into the center to form a double bond.
That’s all, now both carbon atoms have full outer shells since each of them has 8 electrons(2 single bonds means 4 electrons + 1 double bond means 4 electrons).
Now just check the formal charge for the above structure to verify its stability.
6. Check the stability with the help of a formal charge concept
The lesser the formal charge on atoms, the better is the stability of the lewis diagram.
To calculate the formal charge on an atom. Use the formula given below-
The molecular geometry of C2H2Cl2 with respect to both carbon atoms is trigonal planar. Since both carbon central atom is bonded with three atoms(one hydrogen, one chlorine, and one another carbon) and it has no lone pair which means, it is an AX3 type molecule which implies its geometry will be trigonal planar.
A represent central atom
X represent the number of bonded atom to central atom
According to VSEPR theory or chart, the AX3 type molecule forms trigonal planar molecular geometry or shape.
Isomers of C2H2Cl2
There are three isomers possible for C2H2Cl2. The three isomers are –
1,1-Dichloroethene
Cis-1,2-Dichloroethene
Trans-1,2-Dichloroethene
Is C2H2Cl2 polar or nonpolar?
Is C2H2Cl2 polar or non-polar? C2H2Cl2 exists as three isomers. Two isomers of C2H2Cl2 are polar and one isomer is nonpolar.
Three isomers of C2H2Cl2 is –
1,1-Dichloroethene
Cis-1,2-Dichloroethene
Trans-1,2-Dichloroethene
The two isomers of C2H2Cl2 – 1, 1-Dichloroethene, and Cis-1, 2-Dichloroethene are polar. In a polar molecule, “the individual bond dipoles do not cancel each other. Hence, the molecule has a net non-zero dipole moment”.
The one isomer of C2H2Cl2 – Trans-1, 2-Dichloroethene is nonpolar. In the nonpolar isomer, “the individual bond dipoles cancel each other. Hence, the molecule has zero net dipole moment”.
How many isomers exist for C2H2Cl2? Also, tell which is polar or nonpolar?
There are three isomers possible for C2H2Cl2.
1,1-Dichloroethene isomer (Polar)
Cis-1,2-Dichloroethene isomer (Polar)
Trans-1,2-Dichloroethene isomer (Nonpolar)
Why the molecular geometry of C2H2Cl2 is trigonal planar?
The lewis structure of C2H2Cl2 has two central atoms, both are carbon. Each carbon atom is attached to three atoms(one hydrogen, one chlorine, and one another carbon). Hence, the carbon atom has three regions of electron density.
According to VSEPR theory, the three region of electron density implies that the molecule will be Trigonal planar.
Therefore, the molecular geometry for C2H2Cl2 with respect to both carbon central atoms is Trigonal planar.
How many lone pairs are present in the C2H2Cl2 lewis structure?
The lone pair are represented as dots in the lewis diagram. In the C2H2Cl2 lewis structure, there are 12 dots electrons are present which means 6 lone pairs.
One lone pair means 2 dot electrons.
Hence, the number of lone pairs in the C2H2Cl2 lewis structure is 6. Three lone pairs on each chlorine atom.
Vishal Goyal is the founder of Topblogtenz, a comprehensive resource for students seeking guidance and support in their chemistry studies. He holds a degree in B.Tech (Chemical Engineering) and has four years of experience as a chemistry tutor. The team at Topblogtenz includes experts like experienced researchers, professors, and educators, with the goal of making complex subjects like chemistry accessible and understandable for all. A passion for sharing knowledge and a love for chemistry and science drives the team behind the website. Let's connect through LinkedIn: https://www.linkedin.com/in/vishal-goyal-2926a122b/
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