Lewis structure of C3H6

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The Lewis structure of C₃H₆ contains one double bond and seven single bonds, with three carbons in the center. The left carbon is attached with two hydrogens, center carbon is attached with one hydrogen, and right carbon is attached with three hydrogens. Both hydrogen atom and carbon atom do not have any lone pair.

Steps

By using the following steps, you can easily draw the Lewis structure of C₃H₆.

#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 and hydrogen is a group 1 element. Hence, carbon has four valence electrons and hydrogen has one valence electron.

Now C₃H₆ has three carbon atoms and six hydrogen atoms.

So the total number of valence electrons = (valence electrons of carbon atom × 3) + (valence electrons of hydrogen atom × 6)

Therefore, the total number of valence electrons = 12 + 6 = 18

• 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 carbon as the central atom.

But there are three carbon atoms in C₃H₆. Hence, we can assume any one as the central atom. Let’s assume that center carbon is the central atom.

So now, put three carbons in the center and six hydrogens on either side. And draw the rough skeleton structure for the Lewis structure of C₃H₆ something like this:

Also read: How to draw Lewis structure of ICl₅ (4 steps)

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since three carbons are surrounded by six hydrogens, use sixteen electrons to show eight chemical bonds as follows:

#3 Mark lone pairs

As calculated earlier, we have a total of 18 valence electrons. And in the above structure, we have already used sixteen valence electrons. Hence, two valence electrons are remaining.

And two valence electrons represent one lone pair.

Note that carbon is a period 2 element, so it can not keep more than 8 electrons in its 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, left carbon, 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 left carbon will get one lone pair. And the remaining carbon atoms will not get any lone pair, because all lone pairs are used.

Now draw the Lewis structure of C₃H₆ something like this:

In the above structure, you can see that the octet is completed on outside atoms. But, the central atom (center 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 C₆H₆ (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 center carbon already has six valence electrons. Hence, center carbon needs two more valence electrons to complete its octet.

So convert one lone pair from the left carbon atom to make a new bond with the center carbon atoms. And then, the Lewis structure of C₃H₆ looks something like this:

In the above structure, you can see that the octet is completed on the central atom (center 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 SBr₂ (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

Mention the formal charges of atoms on the structure. So the Lewis structure of C₃H₆ looks something like this:

In the above structure, you can see that the formal charges of both (carbon and hydrogen) are zero. Therefore, this is the stable Lewis structure of C₃H₆.

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

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Related

• Lewis structure of ICl₅
• Lewis structure of C₆H₆
• Lewis structure of SBr₂
• Lewis structure of NBr₃
• Lewis structure of HOCl

External links

• Chemical Bonding: C3H6 Lewis Structure – The Geoexchange
• C3H6 (Propene) Lewis Structure in 3 Steps (With Images) – Pediabay
• C3H6 Lewis structure, Hybridization, Molecular geometry, Polarity – Topblogtenz
• How is the Lewis structure for C3H6 determined? – Quora
• Draw the Lewis structure for C3H6 (propene) – Homework.Study.com
• how is c3h6 lewis structure? – Brainly
• Draw the Lewis structures of two isomers of C3H6 – Chegg
• Which of these is a proper Lewis structure of propylene, C3H6 – Bartleby