Acetone (also known as Propanone or C3H6O) lewis structure has three Carbon atoms (C) in a row, which has one Oxygen atom (O) double bonded with the central Carbon atom (C) and three Hydrogen atoms (H) single bonded with each outer Carbon atoms (C). There are 2 lone pairs on the Oxygen atom (O).
Steps of drawing Acetone (C3H6O) lewis structure
Step 1: Find the total valence electrons in C3H6O molecule
In order to find the total valence electrons in a C3H6O molecule, first of all you should know the valence electrons present in carbon atom, hydrogen atom as well as oxygen atom.
(Valence electrons are the electrons that are present in the outermost orbit of any atom.)
Here, I’ll tell you how you can easily find the valence electrons of carbon, hydrogen as well as oxygen using a periodic table.
Total valence electrons in C3H6O molecule
→ Valence electrons given by carbon atom:
Carbon is group 14 element on the periodic table.  Hence the valence electrons present in carbon is 4.
You can see the 4 valence electrons present in the carbon atom as shown in the above image.
→ Valence electrons given by hydrogen atom:
Hydrogen is group 1 element on the periodic table.  Hence the valence electron present in hydrogen is 1.
You can see that only 1 valence electron is present in the hydrogen atom as shown in the above image.
→ Valence electrons given by oxygen atom:
Oxygen is group 16 element on the periodic table.  Hence the valence electrons present in oxygen is 6.
You can see the 6 valence electrons present in the oxygen atom as shown in the above image.
Total valence electrons in C3H6O molecule = valence electrons given by 3 carbon atoms + valence electrons given by 6 hydrogen atoms + valence electrons given by 1 oxygen atom = 4(3) + 1(6) + 6 = 24.
Step 2: Prepare the rough sketch
Lewis structure of acetone has three carbon atoms in a row which has one oxygen atom attached to the central carbon atom. The hydrogen atoms are attached with the two outer carbon atoms. The oxygen atom is double bonded with the carbon atom while the hydrogen atoms are single bonded with the carbon atoms.
Step 3: Make the outer atoms stable
Here in the sketch of C3H6O molecule, you can see that the outer atoms are hydrogen atoms and oxygen atom.
The hydrogen atoms are stable as they have 2 electrons (because hydrogen requires only 2 electrons to form a stable duplet).
So now let’s make the oxygen atom stable by forming an octet on it.
Now you can see that all the outer atoms are stable.
Also, in step 1 we have calculated the total number of valence electrons present in the C3H6O molecule.
The C3H6O molecule has a total 24 valence electrons and all these valence electrons are used in the above sketch of C3H6O.
Hence the above lewis structure of C3H6O (or acetone) is a stable structure.
I hope you have understood the above steps.
For more practice and better understanding, you can try other lewis structures listed below.
Try (or atleast See) these lewis structures for better understanding:
|HNO2 Lewis Structure
|HCO3- Lewis Structure
|C3H8 (Propane) Lewis Structure
|CH3CN Lewis Structure
|SF3- Lewis Structure
|CH3Br Lewis Structure
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