Drawing the Lewis Structure for PCl3

Viewing Notes:

  • PCl3 is similar to PBr3 and PF3. If you can do those Lewis structures PCl5 will be easy.
  • In the PCl3 Lewis structure Phosphorus (P) is the least electronegative so it goes in the center.
  • In the Lewis structure for PCl3 there are a total of 26 valence electrons. hree pairs will be used in the chemical bonds between the P and Cl.

Transcript: Hi, this is Dr. B. Let's do the Lewis structure for PCl3. Phosphorus, on the periodic table, is in group 5, it has 5 valence electrons. Chlorine, group 7, but we have three of those so we have 5 plus 7 (times 3 is 21) is 26 valence electrons. We'll put the Phosphorus in the center and then we'll put the Chlorines around it, just like that. We'll put a pair of electrons between each Chlorine and Phosphorus to form a chemical bond. We've used 6; so we have 6, 8, 10, and 24. We have two more left over, but we need to have two around the Phosphorus to give it an octet, so we'll put those on the central atom. Twenty-six valence electrons. So all of the Chlorines have 8 valence electrons. They have octets, and their outer shells are full. And the Phosphorus has 8 valence electrons, so it has an octet.

We've used all 26 valence electrons, everything has octets: so this is the Lewis structure for PCl3. This is Dr. B., and thanks for watching.