The Lewis structure of CH2F2 contains four single bonds, with carbon in the center, and two hydrogens and two fluorines on either side. There are three lone pairs on each fluorine 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 CH2F2.
#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… carbon is a group 14 element, hydrogen is a group 1 element, and fluorine is a group 17 element. Hence, carbon has four valence electrons, hydrogen has one valence electron, and fluorine has seven valence electrons.
Now CH2F2 has one carbon atom, two hydrogen atoms, and two fluorine atoms.
So the total number of valence electrons = valence electrons of carbon atom + (valence electrons of hydrogen atom × 2) + (valence electrons of fluorine atom × 2)
Therefore, the total number of valence electrons = 4 + 2 + 14 = 20
- 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 fluorine.
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 fluorine as follows:
Electronegativity value of carbon = 2.55
Electronegativity value of fluorine = 3.98
Obviously, carbon is less electronegative than fluorine. Hence, assume that carbon is the central atom.
So now, put carbon in the center and hydrogens and fluorines on either side. And draw the rough skeleton structure for the Lewis structure of CH2F2 something like this:
Also read: How to draw Lewis structure of CH3– (4 steps)
#2 Show chemical bond
Place two electrons between the atoms to show a chemical bond. Since carbon is surrounded by two hydrogens and two fluorines, use eight electrons to show four chemical bonds as follows:
Also read: How to draw Lewis structure of NH2– (4 steps)
#3 Mark lone pairs
As calculated earlier, we have a total of 20 valence electrons. And in the above structure, we have already used eight valence electrons. Hence, twelve valence electrons are remaining.
Two valence electrons represent one lone pair. So twelve valence electrons = six lone pairs.
Note that both (carbon and fluorine) are the period 2 elements, so they can not keep more than 8 electrons in their last shell. And hydrogen is a period 1 element, so it can not keep more than 2 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 and fluorines. But hydrogen can not keep more than 2 electrons in its last shell. Hence, don’t mark the lone pairs on hydrogen.
So each fluorine will get three lone pairs. And the central atom (carbon) will not get any lone pair, because all six lone pairs are used.
Now draw the Lewis structure of CH2F2 something like this:
In the above structure, you can see that the octet is completed on the central atom (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 acetone (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 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 fluorine 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 CH2F2 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 CH2F2.
And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.
Related
- Lewis structure of CH3–
- Lewis structure of NH2–
- Lewis structure of acetone
- Lewis structure of NI3
- Lewis structure of ICl2–
External video
- CH2F2 Lewis Structure – How to Draw the Lewis Structure for CH2F2 – YouTube • Wayne Breslyn
External links
- CH2F2 Lewis structure, Molecular geometry, Hybridization, Bond angle – Topblogtenz
- CH2F2 Lewis Structure in 6 Steps (With Images) – Pediabay
- Chemical Bonding: CH2F2 Lewis Structure – The Geoexchange
- CH2F2 Lewis structure, Hybridization, Molecular Structure, and Bond Angles – Geometry of Molecules
- CH2F2 Lewis Structure, Molecular Geometry, Hybridization, and Polarity – Techiescientist
- When drawing the Lewis structure of a molecule, such as CH2F2, how do I know where to place the outer elements? – Quora
- Draw the Lewis structure for CH2F2. How many bonds are around the central atom, and what is the shape of this molecule? – Homework.Study.com
- Draw the best Lewis structure for CH2F2 – Chegg
- How to draw CH2F2 Lewis Structure? – Science Education and Tutorials
- Referring to the most stable Lewis dot structure of CH2F2, what is its molecular geometry? – 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.