Jump to content

Chemistry octet rule


Rachel Maddiee

Recommended Posts

Phosphorus pentachloride (PCI5) is an exception to the octet rule because it has more than 8 electrons around the valence shell. The chlorine atoms (PCI3) obey the octet rule because the atom has five electrons and need three to fulfill its octet, while the phosphorus atom does not. Phosphorus (PCI5) can form an expanded octet containing ten electrons in the 3d orbitals.

is this correct?

EFA14151-5F04-4E1F-AAE2-F6302013A2B7.png

Link to comment
Share on other sites

I would delete the very last part about 3d orbitals and just end with 10 electrons. Also, this:

1 hour ago, Rachel Maddiee said:

The chlorine atoms (PCI3) obey the octet rule because the atom has five electrons and need three to fulfill its octet, while the phosphorus atom does not.

Doesn't make a lot of sense. The chlorine atoms in PCl3 and PCl5 have 7 valence electrons. Where did you get 5 from? Besides this, your answer is mostly okay but you could explain it a little better. For example, why does PClneed to have an expanded octet around the phosphorus? This is the crux of the question, but I don't think you've given a good enough explanation for why it is. 

Link to comment
Share on other sites

22 minutes ago, Rachel Maddiee said:

n order for the P atom to form bonds with 5 Cl atoms, it must have an expanded octet. 

 

Yes, though I wouldn't recommend directly copy pasting from another website when their background is quite so blue if you don't want to be caught out plagiarising (I assume that came from here https://lavelle.chem.ucla.edu/forum/viewtopic.php?t=23108). You should try and think about it yourself next time.  

Link to comment
Share on other sites

Yes, I’m aware. I couldn’t find anything in my reference book so I was trying to find a better explanation online. 

Phosphorus pentachloride (PCI5) is an exception to the octet rule because it has more than 8 electrons around the valence shell. Phosphorus (PCI5) can form an expanded octet containing ten electrons. The central phosphorus atom is bonded to five chlorine atoms. While PCI3 contains a phosphorus atom with an octet.
 

How is this?

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.