Drawing the Lewis Structure for HI

Viewing Notes:

  • HI is very similar to HF and HCl. Hydrogen has 1 valence electron and Iodine (in Group 7 with F and Cl) has 7 valence electrons.
  • With the Lewis Structure for HI remember that Hydrogen only needs 2 valence electrons to have a full outer shell.
  • Be sure that you don’t use more than the 8 valence electrons available.

Transcript: Hello, this is Dr. B. and we're going to do HI, hydroiodic acid, the acid that's happy to see you. So let's start on the periodic table. We can see that Hydrogen has 1 valence electron, and in group 7, or sometimes called 17, Iodine has 7 valence electrons. One plus 7 equals 8. So we have a total of 8 valence electrons that we're going to use to form chemical bonds and fill the octets of atoms. Start by drawing H and then I. Sometimes you can put this up here and make it really look like an I. So we have 8 valence electrons. Let's put two here to bond the Hydrogen and the Iodine atoms. And that fulfills the octet, really the duet, of Hydrogen. Hydrogen only needs two to have a full outer shell.

So we've used 2, 4, 6, 8. Now the Iodine has a total of 2, 4, 6, 8. Its outer shell is full. And we've used 2, 4, 6, 8; the eight valence electrons that we were given. So we've fulfilled the octet rule, everything has a full outer shell, and we've used the 8 valence electrons that we were given. We could also take and write the structural formula for hydroiodic acid, and that'll look like this right here, where these two bonding electrons will be represented by a single bond right there.

That's it: hydroiodic acid, the Lewis structure. This is Dr. B., and thanks for watching.