octet exceptions

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Guzman_1J
Posts: 72
Joined: Wed Sep 18, 2019 12:16 am

octet exceptions

Postby Guzman_1J » Wed Nov 06, 2019 1:45 am

Which are the elements that can have an expanded octet and by how much? I know P is 10, S is 12, but what about the other ones

Justin Sarquiz 2F
Posts: 106
Joined: Fri Aug 30, 2019 12:15 am

Re: octet exceptions

Postby Justin Sarquiz 2F » Wed Nov 06, 2019 9:03 am

The exceptions to the octet rule are P, S, and Cl because they have an unfilled d subshell. However, I do not know the maximum amount of electrons they can hold, but I do not think that it is that relevant. Just know that these three elements can have more than 8 electrons.

Michael Nguyen 1E
Posts: 120
Joined: Sat Aug 17, 2019 12:17 am

Re: octet exceptions

Postby Michael Nguyen 1E » Wed Nov 06, 2019 9:49 am

There are other exceptions that can have expanded octets beyond just P, S, and Cl. Any element that would have unfilled d-orbitals able to be used would be able to accommodate extra electrons and have an expanded octet. It's just that the first ones that are able to do this are P, S, and Cl.

Ariel Davydov 1C
Posts: 110
Joined: Thu Jul 11, 2019 12:16 am
Been upvoted: 1 time

Re: octet exceptions

Postby Ariel Davydov 1C » Wed Nov 06, 2019 10:44 am

In addition, with elements with expanded octets, the best way to determine the amount of extra electrons they typically store is through calculating its formal charge. For example, with S, if it forms four bonds with other elements, it will typically have one additional lone pair of electrons in order to keep its formal charge at zero (FC = 6 valence e - (2 lone pair e + 8 paired e/2) = 6 - (2 + 4) = 6 - 6 = 0).


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