Lewis structure of ethanol

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The Lewis structure of ethanol CH₃CH₂OH contains eight single bonds, with two carbons in the center, and oxygen and six hydrogens on either side. There are two lone pairs on the oxygen 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 ethanol:

#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 oxygen is a group 16 element. Hence, carbon has four valence electrons, hydrogen has one valence electron, and oxygen has six valence electrons.

Now ethanol, CH₃CH₂OH has two carbon atoms, six hydrogen atoms, and one oxygen atom.

So the total number of valence electrons = (valence electrons of carbon atom × 2) + (valence electrons of hydrogen atom × 6) + valence electrons of oxygen atom

Therefore, the total number of valence electrons = 8 + 6 + 6 = 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 oxygen.

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 oxygen as follows:

Electronegativity value of carbon = 2.55
Electronegativity value of oxygen = 3.44

Obviously, carbon is less electronegative than oxygen. Hence, assume that left carbon is the central atom (as there are two carbons).

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

Also read: How to draw Lewis structure of N₂H₄ (4 steps)

#2 Show chemical bond

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

Also read: How to draw Lewis structure of HBr (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 sixteen valence electrons. Hence, four valence electrons are remaining.

Two valence electrons represent one lone pair. So four valence electrons = two lone pairs.

Note that both (carbon and oxygen) 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, oxygen, 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 oxygen will get two lone pairs. And right carbon and the central atom (left carbon) will not get any lone pair, because all two lone pairs are used.

Now draw the Lewis structure of ethanol something like this:

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 H₂SO₄ (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 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 oxygen atom

Valence electrons = 6
Nonbonding electrons = 4
Bonding electrons = 4

Formal charge = 6 – 4 – ½ (4) = 0

Mention the formal charges of atoms on the structure. So the Lewis structure of ethanol 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 ethanol.

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

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Related

• Lewis structure of N₂H₄
• Lewis structure of HBr
• Lewis structure of H₂SO₄
• Lewis structure of OH^–
• Lewis structure of SiH₄

External video

• How to Draw the Lewis Dot Structure for C2H5OH: Ethanol (Ethyl alcohol) – Wayne Breslyn

External links

• Ethanol (CH3CH2OH) Lewis Structure – Chemistry School
• C2H5OH (Ethanol) Lewis Structure in 6 Steps – Pediabay
• C2H5OH Lewis Structure, Molecular Geometry, Hybridization, and Polarity – Techiescientist
• Write the Lewis structure for ethanol (CH3CH2OH), the alcohol found in alcoholic beverages – Brainly
• C2H5OH Lewis structure, molecular geometry, hybridization, bond angle – Topblogtenz
• Draw C2H5OH (ethanol) Lewis structure – Proprep
• C2H5OH Lewis Structure, Molecular Geometry, Bond Angles and Hybridization – Geometry of Molecules
• Draw a Lewis structure for ethanol (C2H5OH) – Chegg
• What is Ethanol? Lewis Structure, Molar Mass, Formal Charge and Molecular Geometry – ChemWhite
• Lewis Dot of Ethanol CH3CH2OH – Kent’s Chemistry
• Lewis structure of Ethanol – Science Education and Tutorials
• How can you determine the Lewis structure for C2H5OH? – Quora
• ethanol lewis structure – Wolfram Alpha
• File:Ethanol Lewis.svg – Wikimedia Commons
• What is the Lewis dot structure of ethanol? – Answers
• What is the Lewis structure for ethanol, CH3CH2OH? – OneClass
• Write the Lewis structure for ethanol (CH3CH2OH), the alcohol found in alcoholic beverages – Bartleby
• Ethanol (CH3OH) has the Lewis structure shown below. Determine the shape of the molecule around each carbon and oxygen, as indicated – Numerade
• Ethanol dot and cross – ShowMe