The Lewis structure of C2H2Cl2 contains one double bond and four single bonds, with two carbons in the center, and each carbon is attached with one hydrogen and one chlorine. There are three lone pairs on each chlorine atom, and carbon atom and hydrogen atom do not have any lone pair.
Steps
By using the following steps, you can easily draw the Lewis structure of C2H2Cl2.
#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Complete octet on central atom
#5 Calculate formal charge and check stability
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… carbon is a group 14 element, hydrogen is a group 1 element, and chlorine is a group 17 element. Hence, carbon has four valence electrons, hydrogen has one valence electron, and chlorine has seven valence electrons.
Now C2H2Cl2 has two carbon atoms, two hydrogen atoms, and two chlorine atoms.
So the total number of valence electrons = (valence electrons of carbon atom × 2) + (valence electrons of hydrogen atom × 2) + (valence electrons of chlorine atom × 2)
Therefore, the total number of valence electrons = 8 + 2 + 14 = 24
- 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.
Therefore, choose the central atom from carbon and chlorine.
The atom with the least electronegative value is placed at the center. By looking at the periodic table, we get the electronegativity values for carbon and chlorine as follows:
Electronegativity value of carbon = 2.55
Electronegativity value of chlorine = 3.16
Obviously, carbon is less electronegative than chlorine. Hence, assume that left carbon is the central atom (as there are two carbons).
So now, put two carbons in the center and two hydrogens and two chlorines on either side. And draw the rough skeleton structure for the Lewis structure of C2H2Cl2 something like this:
Also read: How to draw Lewis structure of C22- (5 steps)
#2 Show chemical bond
Place two electrons between the atoms to show a chemical bond. Since two carbons are surrounded by two hydrogens and two chlorines, use ten electrons to show five chemical bonds as follows:
#3 Mark lone pairs
As calculated earlier, we have a total of 24 valence electrons. And in the above structure, we have already used ten valence electrons. Hence, fourteen valence electrons are remaining.
Two valence electrons represent one lone pair. So fourteen valence electrons = seven lone pairs.
Note that carbon is a period 2 element, so it can not keep more than 8 electrons in its last shell. 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 atoms are hydrogens, chlorines, and right carbon. But hydrogen can not keep more than 2 electrons in its last shell. Hence, don’t mark the lone pairs on hydrogen.
So each chlorine will get three lone pairs, and the right carbon will get one lone pair. And the central atom (left carbon) will not get any lone pair, because all seven lone pairs are used.
Now draw the Lewis structure of C2H2Cl2 something like this:
In the above structure, you can see that the octet is completed on outside atoms. But, the central atom (left carbon) doesn’t form an octet.
So in the next step, we have to complete the octet on the central atom.
Also read: How to draw Lewis structure of SeO32- (5 steps)
#4 Complete octet on central atom
Remember that carbon is a period 2 element, so it can not keep more than 8 electrons in its last shell.
Now left carbon already has six valence electrons. Hence, left carbon needs two more valence electrons to complete its octet.
So convert one lone pair from the right carbon atom to make a new bond with the left carbon atom. And then, the Lewis structure of C2H2Cl2 looks something like this:
Here, the lone pair of carbon is converted (instead of chlorine). This is because carbon is less electronegative than chlorine, and so it can give more electrons to share them.
In the above structure, you can see that the octet is completed on the central atom (left carbon), and also on the outside atoms. 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 P4 (4 steps)
#5 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 each carbon atom
Valence electrons = 4
Nonbonding electrons = 0
Bonding electrons = 8
Formal charge = 4 – 0 – ½ (8) = 0
- For each hydrogen atom
Valence electrons = 1
Nonbonding electrons = 0
Bonding electrons = 2
Formal charge = 1 – 0 – ½ (2) = 0
- For each 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 C2H2Cl2 looks something like this:
In the above structure, you can see that the formal charges of all atoms are zero. Therefore, this is the stable Lewis structure of C2H2Cl2.
And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.
Related
- Lewis structure of C22-
- Lewis structure of SeO32-
- Lewis structure of P4
- Lewis structure of ClF
- Lewis structure of NH2OH
External links
- Chemical Bonding: C2H2Cl2 Lewis Structure – The Geoexchange
- C2H2Cl2 Lewis structure, Molecular geometry, Polar or nonpolar, Isomers – Topblogtenz
- C2H2Cl2 Lewis Structure in 6 Steps (With Images) – Pediabay
- How can you determine the Lewis dot structure for C2H2Cl2? – Quora
- Draw and explain the Lewis structure for C2H2Cl2 – Homework.Study.com
- C2H2Cl2 molecular geometry – Chemical Forums
- Draw the Lewis Structure for dichloroethane, C2H2Cl2 – Chegg
- This is the correct Lewis structure for the molecule C2H2Cl2? – Brainly
Deep
Rootmemory.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.