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Lewis Structure Octet Rule Exceptions

Posted: Tue Oct 25, 2016 3:24 pm
by Junghyuk_Park_1I
I understand that the Lewis Structures depend on formal charge and octet rule (with formal charge being more important), but I had the following question:

Which elements tend to be/can be octet exceptions (example Boron can have 3 bonds as well as other elements with expanded octets)?
Is there a way to tell?
Is there a row it begins on?

Thank you in advance.

Re: Lewis Structure Octet Rule Exceptions

Posted: Tue Oct 25, 2016 3:54 pm
by Tara_Shooshani_3N
H, He, Li, and Be are exceptions since they cannot hold 8 electrons.
As for elements that have expanded octets, most of the elements after Si have expanded octets since they're in the third energy level (third row of the periodic table) and have empty d orbitals. I've specifically seen a lot of P and S with expanded orbitals.

Re: Lewis Structure Octet Rule Exceptions

Posted: Tue Oct 25, 2016 5:22 pm
by Zsanielle Moncayo 1E
How do you know by how much an element can break the octet rule? For example, how do we know Phosphorus is allowed to have 5 bonds?

Re: Lewis Structure Octet Rule Exceptions

Posted: Tue Oct 25, 2016 6:01 pm
by 404757006
What is the best way to recognize when an element has an expanded octet? Is it only the specific elements or does it have to do with its placement on the periodic table?

Re: Lewis Structure Octet Rule Exceptions

Posted: Tue Oct 25, 2016 11:15 pm
by nick_pantoja_3G
P, S, Cl can have expanded 8e-. However, Typically Cl is not a central atom as it has a high ionization energy.