Drawing the Lewis Structure for C3H6

Viewing Notes:

  • With C3H6 there are two possible Lewis structures that can be drawn. Both are "correct" in that they full the outer shells of each atom in the structure and use the exact number of valence electrons available for the C3H6 Lewis structure..
  • Remember that Hydrogen (H) atoms always go on the outside of a Lewis Structure.
  • Note that Hydrogen only needs two valence electrons to have a full outer shell.

This is the C3H6 Lewis structure. For C3H6 we have a total of 18 valence electrons. The thing about C3H6, is there's more than one way to draw it based on the chemical formula that we're given here. So let's look at the two ways you can draw the C3H6 Lewis structure.

The first structure is called cyclopropane. When we see "cyclo", we're thinking ring. So here you can see we've used 18 valence electrons. Each of the Carbons has four things bonded to it, has four single bonds. Each bond has 2 valence electrons. So the Carbons all have octets. And then the Hydrogens each have a single bond, so they have two valence electrons, so their outer shells are full as well. This is one possible structure for C3H6. We've used 18 valence electrons, the octets are satisfied for each of the atoms. So cyclopropane is one option.

Another option is propene, where we have each Carbon having, again, four single bonds, the octets are full for the carbons. The Hydrogens, they all have a single bond themselves, as well, so they have 2 valence electrons, and their outer shells are full. Again, we've used 18 valence electrons, we've satisfied the octets for each of the atoms, so this is the other possible structure for C3H6. If you're given the C3H6 formula, either structure would be correct.

So that's the Lewis structure for C3H6. This is Dr. B., and thanks for watching.