Exceptions to the octet rule

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Stevin1H
Posts: 89
Joined: Fri Sep 28, 2018 12:17 am

Exceptions to the octet rule

Postby Stevin1H » Thu Nov 08, 2018 12:28 pm

Can someone explain why certain elements like Boron or Aluminum can still form a stable structure with only 6 electrons? Why does this exception to the octet rule work/make sense?

Nada AbouHaiba 1I
Posts: 77
Joined: Fri Sep 28, 2018 12:28 am
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Re: Exceptions to the octet rule

Postby Nada AbouHaiba 1I » Thu Nov 08, 2018 12:35 pm

Group 13 elements are an exception to the octet rule because in order for them to get an octet they need to form 5 bonds which they're unable to do.
Then any element in the third row or lower is able to have an expanded octet because they have access to an empty d orbital

Tiffany_Cacy_3D
Posts: 70
Joined: Fri Sep 28, 2018 12:24 am

Re: Exceptions to the octet rule

Postby Tiffany_Cacy_3D » Thu Nov 08, 2018 12:39 pm

Group 13 elements only have three electrons available to make bonds. They can only accept three more because once they have six there are no more electrons available to bond with.

Hailey Boehm 2H
Posts: 71
Joined: Fri Sep 28, 2018 12:24 am

Re: Exceptions to the octet rule

Postby Hailey Boehm 2H » Thu Nov 08, 2018 12:43 pm

Also, to add on, Boron and Aluminum are involved in lewis acid-base reactions. B and Al sometimes can readily form compounds that do not obey the octet rule, but these B and Al compounds can complete their octet when they react with a lewis base. The lewis base donates its e-'s to form a coordinate covalent bond with the B or Al compound, thus completing its octet.


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