C5H12 Lewis structure

C₅H₁₂ (pentane) has five carbon atoms and twelve hydrogen atoms.

In the C₅H₁₂ Lewis structure, there are four single bonds between the five carbon atoms. The left carbon and right carbon are attached with three hydrogen atoms, and the three center carbons are attached with two hydrogen atoms. And none of the atoms has a lone pair.

Alternative method: Lewis structure of C₅H₁₂

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 C₅H₁₂ has five carbon atoms and twelve hydrogen atoms, so…

Valence electrons of five carbon atoms = 4 × 5 = 20
Valence electrons of twelve hydrogen atoms = 1 × 12 = 12

And the total valence electrons = 20 + 12 = 32

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

• Second, find the total electron pairs

We have a total of 32 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 = 32 ÷ 2 = 16

• 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 five atoms remaining and all five atoms are carbon, so we can assume any one as the central atom.

Let’s assume that the central atom is right 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 16 electron pairs. And sixteen 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 C₅H₁₂ consists of a continuous chain of five carbon atoms, with hydrogen atoms linked to each carbon to fill their remaining valencies. In this arrangement, each of the five carbon atoms forms four single covalent bonds to satisfy the octet rule, while every hydrogen atom achieves a stable duet. Within this layout, the three internal carbon atoms are each bonded to two other carbons and two hydrogens, whereas the two terminal carbon atoms are bonded to one carbon and three hydrogens. This configuration represents the most stable state for the linear molecule because it results in a formal charge of zero for every atom involved. Consequently, this specific electronic distribution serves as the definitive and most accurate Lewis representation of n-pentane.

Next: XeF₆ Lewis structure

External video

• How to Draw the Lewis Dot Structure for C5H12: Pentane – YouTube • Wayne Breslyn