Drawing the Lewis Structure for HCCH

Viewing Notes:

  • HCCH (Ethyne) can also be written as C2H2.
  • Ethyne is also called Acetylene.
  • For the HCCH Lewis structure you'll need to form a triple bond between the two carbon atoms.
  • Hydrogen atoms only need two electrons for a full outer shell.
  • There are a total of 10 valence electrons for the HCCH Lewis structure.

Transcript: This is the HCCH Lewis structure. For HCCH, we have a total of 10 valence electrons. We'll put the Carbons at the center, Hydrogens always go on the outside like this. We'll put 2 electrons between the atoms to form chemical bonds. We've used 6, and we have 10, so we'll go 8 and 10. At this point, the Hydrogens both have 2 valence electrons, so their outer shells are full; and this Carbon has 8, so it has an octet; but we only have 4 valence electrons on this Carbon.

What we can do is take 2 of these valence electrons and move them to the center to form a double bond. We're sharing those valence electrons now between the Carbons. So now we still have 8 on this Carbon, but this Carbon has 6, so we're getting closer to an octet. We're still only using 10 valence electrons. Let's move 2 more to the center to form a triple bond. We have 8 here, still, but now we have 8 on this Carbon. We're still using the 10 valence electrons we have for the HCCH Lewis structure.

So with that, we're done. This is the Lewis structure for HCCH. This is Dr. B., and thanks for watching.