Drawing the Lewis Structure for CO2

Viewing Notes:

  • CO2 is a clear, heavier-than-air gas. In the Earth's atomsphere it is considered a greenhouse gas.
  • In the CO2 Lewis structure carbon is the least electronegative element. Therefore it is put in the center of the dot structure.
  • For the CO2 Lewis structure there are a total of 16 valence electrons available.

Transcript: OK, this is Dr. B. We're going to do the Lewis structure for CO2, Carbon dioxide. On the periodic table, Carbon is in group 4, or 14 sometimes; and then Oxygen is in group 6 or 16. But we have two of them. So let's multiply that together there: so we have 12 plus 4, 16 total valence electrons. Let's draw the structure. Carbon is the least electronegative; that means it's going to go at the center. So we'll put the Carbon right here, and then Oxygens on either side of that.

So now we want to draw some chemical bonds. Let's put a pair of electrons between each of these, so now they're bonded. We've used four. Then let's complete the octets on the outer shell. So, 4, 6, 8, 10, 12, 14, 16. That looks pretty good: looks like it kind of works out the way we want it to. Let's check and see if we have octets. This Oxygen here has 8. This Oxygen here has 8. They both have octets. The Carbon only has 4 valence electrons, it doesn't have an octet.

What we can do is, we can share electrons--these nonbonding electrons out here between the atoms there. Now we have 2, 4, 6, 8; that Oxygen's OK. The Carbon has 2, 4, 6. Little bit closer. Let's take some electrons over here and share them on this side so that Oxygen has 8, we still have 8 over here. And now Carbon in the center has 2, 4, 6, 8. So we've completed the octet. And if you add them up, 2, 4, 6, 8, 10, 12, 14, 16, we've used 16 valence electrons. That's all we had to start out with. Let's clean that up there. If we wanted to write this as a structural formula, we could also do that and that would look like this. In this structural formula, the two lines right here are the same as these two pairs of valence electrons.

This is Dr. B., and thank you for watching.