C3H8 Lewis structure

C₃H₈ (propane) has three carbon atoms and eight hydrogen atoms.

In the C₃H₈ Lewis structure, there are two single bonds between the three carbon atoms. The left carbon and right carbon are attached with three hydrogen atoms, and the center carbon is attached with two hydrogen atoms. And none of the atoms has a lone pair.

Alternative method: Lewis structure of C₃H₈

Rough sketch

• First, determine the total number of valence electrons

In the periodic table, carbon lies in group 14, and hydrogen lies in group 1.

Hence, carbon has four valence electrons and hydrogen has one valence electron.

Since C₃H₈ has three carbon atoms and eight hydrogen atoms, so…

Valence electrons of three carbon atoms = 4 × 3 = 12
Valence electrons of eight hydrogen atoms = 1 × 8 = 8

And the total valence electrons = 12 + 8 = 20

Learn how to find: Carbon valence electrons and Hydrogen valence electrons

• Second, find the total electron pairs

We have a total of 20 valence electrons. And when we divide this value by two, we get the value of total electron pairs.

Total electron pairs = total valence electrons ÷ 2

So the total electron pairs = 20 ÷ 2 = 10

• Third, determine the central atom

Here hydrogen can not be 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.

Now there are three atoms remaining and all three atoms are carbon, so we can assume any one as the central atom.

Let’s assume that the central atom is center carbon.

Therefore, place carbons in the center and hydrogens on either side.

• And finally, draw the rough sketch

Lone pair

Here, we have a total of 10 electron pairs. And ten bonds are already marked. So we do not have to mark any electron pair as a lone pair on the sketch.

Final structure

The final structure of C₃H₈ contains a chain of three carbon atoms linked by single covalent bonds, with eight hydrogen atoms attached to the remaining available bonding sites. In this arrangement, the central carbon atom bonds to two hydrogens while the two terminal carbon atoms each bond to three hydrogens, ensuring that every carbon atom satisfies the octet rule. Each hydrogen atom simultaneously achieves its stable duet through these single bonds, resulting in formal charges of zero across the entire molecule. Consequently, this saturated hydrocarbon chain represents the most stable and chemically accurate Lewis representation of propane.

Next: CH₃CN Lewis structure

External video

• How to Draw the Lewis Structure for C3H8 (Propane) – YouTube • Wayne Breslyn

External links

• https://www.thegeoexchange.org/chemistry/bonding/Lewis-Structures/C3H8-lewis-structure.html
• https://topblogtenz.com/propane-c3h8-lewis-structure-molecular-geometry-hybridization-polar-or-nonpolar/
• https://oneclass.com/homework-help/chemistry/7026706-c3h8-lewis-structure.en.html