Drawing the Lewis Structure for NCl3

Viewing Notes:

  • NCl3 is similar to NH3 and NF3. If you can do those Lewis structures NCl3 will be easy.
  • In the NH3 Lewis structure Nitrogen (N) is the least electronegative so it goes in the center.
  • In the Lewis structure for NCl3 there are a total of 26 valence electrons. Three pairs will be used in the chemical bonds between the N and Cl and one pair of electrons will be unbonded.

Transcript: Hi, this is Dr. B. Let's do the Lewis structure for NCl3, nitrogen trichloride. On the periodic table, Nitrogen is in group 5, sometimes called 15, so it has 5 valence electrons. And then Chlorine is in group 7 or 17, and it has 7 valence electrons. We do have three Chlorine atoms, so let's multiply that by three. So 5 plus 21: 26 valence electrons to work with.

Nitrogen's the least electronegative, so Nitrogen goes right there at the center, and we'll put the Chlorines around it like that. And we have 26 valence electrons to distribute around these atoms. Let's put a pair between these atoms to form some chemical bonds, some single bonds. So we've used 6, and then we'll do the outer atoms. Six, 8, 10, 12, 14, 16, 18, 20, 22, 24, and we'll put the last two, 26, right there, and so we've used all 26.

So now we need to look and see if we've fulfilled the octets for each of the atoms. Nitrogen, in the center right there, has 2, 4, 6, 8, so that has an octet. And then each of the Chlorines has eight, as well. So those have octets. We've used all 26 valence electrons. That's it: that's the Lewis structure for NCl3. We can also take and draw it as a structural formula, and that is going to look just like this right here. Pull it in for you...Lewis structure for NCl3.

This is Dr. B., and thanks for watching.