Lewis Structure of C2H5OH (Ethanol) (With 6 Simple Steps!)

I’m super excited to teach you the lewis structure of C2H5OH (ethanol) in just 6 simple steps.

Infact, I’ve also given the step-by-step images for drawing the lewis dot structure of C2H5OH molecule.

So, if you are ready to go with these 6 simple steps, then let’s dive right into it!

Lewis structure of C2H5OH (or Ethanol) contains five C-H bonds, one O-H bond and one C-O bond. The two Carbon atoms (C) are at the center and it is surrounded by Hydrogen atoms (H) and one OH group. The oxygen atom has 2 lone pairs.

Let’s draw and understand this lewis dot structure step by step.

(Note: Take a pen and paper with you and try to draw this lewis structure along with me. I am sure you will definitely learn how to draw lewis structure of C2H5OH).

6 Steps to Draw the Lewis Structure of C2H5OH

Step #1: Calculate the total number of valence electrons

Here, the given molecule is C2H5OH (ethanol). In order to draw the lewis structure of C2H5OH, first of all you have to find the total number of valence electrons present in the C2H5OH molecule.
(Valence electrons are the number of electrons present in the outermost shell of an atom).

So, let’s calculate this first.

Calculation of valence electrons in C2H5OH

• For Carbon:

Carbon is a group 14 element on the periodic table. ^[1]

Hence, the valence electrons present in carbon is 4 (see below image).

• For Hydrogen: 

Hydrogen is a group 1 element on the periodic table. ^[2]

Hence, the valence electron present in hydrogen is 1 (see below image).

• For Oxygen:

Oxygen is a group 16 element on the periodic table. ^[3]

Hence, the valence electron present in oxygen is 6 (see below image).

Hence in a C2H5OH molecule, 

Valence electrons given by each Carbon (C) atom = 4
Valence electron given by each Hydrogen (H) atom = 1
Valence electrons given by each Oxygen (O) atom = 6
So, total number of Valence electrons in C2H5OH molecule = 4(2) + 1(5) + 6 + 1 = 20

Step #2: Select the center atom (H is always outside)

While selecting the center atom, always put the least electronegative atom at the center.

(Remember: Fluorine is the most electronegative element on the periodic table and the electronegativity decreases as we move right to left in the periodic table as well as top to bottom in the periodic table). ^[4]

Here in the C2H5OH molecule, if we compare the carbon atom (C), oxygen atom (O) and hydrogen atom (H), then hydrogen is less electronegative than oxygen and carbon. But as per the rule, we have to keep hydrogen outside.

So, carbon (which is less electronegative than oxygen) should be placed in the center and the remaining hydrogen atoms as well as OH group will surround it.

Step #3: Put two electrons between the atoms to represent a chemical bond

Now in the above sketch of C2H5OH molecule, put the two electrons (i.e electron pair) between the carbon atom, oxygen atom and hydrogen atom to represent a chemical bond between them.

These pairs of electrons present between the Carbon (C), Oxygen (O) and Hydrogen (H) atoms form a chemical bond, which bonds these atoms with each other in a C2H5OH molecule.

Step #4: Complete the octet (or duplet) on outside atoms

Don’t worry, I’ll explain!

In the Lewis structure of C2H5OH, the outer atoms are hydrogen atoms as well as oxygen atom.

Hydrogen already has a duplet (see below image).

So now, you have to complete the octet on oxygen atom (because oxygen requires 8 electrons to have a complete outer shell).

Now, you can see in the above image that the oxygen atom forms an octet.

Also, all the 20 valence electrons of C2H5OH molecule (as calculated in step #1) are used in the above structure. So there are no remaining electron pairs.

Hence there is no change in the above sketch of C2H5OH.

Let’s move to the next step.

Step #5: Check whether the central atom has octet or not

In this step, we have to check whether the central atoms (i.e two carbon atoms) have an octet or not. 

In simple words, we have to check whether the central Carbon (C) atoms has 8 electrons or not.

As you can see from the above image, the central atoms (i.e carbon), has 8 electrons. So it fulfills the octet rule and both the carbon atoms are stable.

Step #6: Final step – Check the stability of lewis structure by calculating the formal charge on each atom

Now, you have come to the final step and here you have to check the formal charge on carbon atom (C), oxygen atom (O) as well as each hydrogen atom (H).

For that, you need to remember the formula of formal charge;

Formal charge = Valence electrons – Nonbonding electrons – (Bonding electrons)/2

• For Carbon:
  Valence electrons = 4 (as it is in group 14)
  Nonbonding electrons = 0
  Bonding electrons = 8
• For Oxygen:
  Valence electron = 6 (as it is in group 16)
  Nonbonding electrons = 4
  Bonding electrons = 4
• For Hydrogen:
  Valence electron = 1 (as it is in group 1)
  Nonbonding electrons = 0
  Bonding electrons = 2

Formal charge	=	Valence electrons	–	Nonbonding electrons	–	(Bonding electrons)/2
C	=	4	–	0	–	8/2	=	0
O	=	6	–	4	–	4/2	=	0
H	=	1	–	0	–	2/2	=	0

So you can see above that the formal charges on carbon, oxygen as well as hydrogen are “zero”.

Hence, there will not be any change in the above structure and the above lewis structure of C2H5OH is the final stable structure only.

Each electron pair (:) in the lewis dot structure of C2H5OH represents the single bond ( | ). So the above lewis dot structure of C2H5OH can also be represented as shown below.

Related lewis structures for your practice:
Lewis structure of BeF2
Lewis structure of OH-
Lewis structure of N2H2
Lewis structure of CH3Cl
Lewis structure of HBr

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