octet exceptions

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Katherine Chhen 3I
Posts: 53
Joined: Fri Sep 28, 2018 12:15 am

octet exceptions

Postby Katherine Chhen 3I » Thu Oct 31, 2019 1:15 pm

How would we know if a molecule is an exception to the octet rule?

Jarrett Peyrefitte 2K
Posts: 102
Joined: Sat Aug 24, 2019 12:16 am

Re: octet exceptions

Postby Jarrett Peyrefitte 2K » Thu Oct 31, 2019 1:21 pm

Molecules that have exceptions to the octet rule are molecules with an odd number of electrons (ex. NO) , molecules in which an atom or more than one atom have more than 8 electrons (ex. SF6) , and molecules in which an atom or more than one atom have less than 8 electrons (ex. BCl3) .

Serena Siddiq 3D
Posts: 51
Joined: Fri Aug 30, 2019 12:17 am

Re: octet exceptions

Postby Serena Siddiq 3D » Thu Oct 31, 2019 1:41 pm

You know if it is an octet exception if you are drawing the Lewis structure and you are not matching up with the amount of electrons it should have because the bonds you make lower the amount of lone pairs to be counted on the separate atom. If this happens, as long as it is the central atom is in period 3 and higher, it can exceed the octet rule because it has access to the d orbital, which can always hold more electrons, even if that specific atom only goes up to a 3s or 3p in its own configuration. So, you can add an extra lone pair or so to the central atom in order to reach the calculated electron count of the molecule to get an accurate structure. Hope that helps!

melinak1
Posts: 25
Joined: Tue Sep 24, 2019 12:17 am

Re: octet exceptions

Postby melinak1 » Thu Oct 31, 2019 1:55 pm

Jarrett Peyrefitte 1L wrote:Molecules that have exceptions to the octet rule are molecules with an odd number of electrons (ex. NO) , molecules in which an atom or more than one atom have more than 8 electrons (ex. SF6) , and molecules in which an atom or more than one atom have less than 8 electrons (ex. BCl3) .



thank you!!!

Jorge Ramirez_4H
Posts: 54
Joined: Wed Nov 21, 2018 12:19 am

Re: octet exceptions

Postby Jorge Ramirez_4H » Thu Oct 31, 2019 2:35 pm

How about elements in the third row?

Kallista McCarty 1C
Posts: 212
Joined: Wed Sep 18, 2019 12:18 am

Re: octet exceptions

Postby Kallista McCarty 1C » Thu Oct 31, 2019 3:10 pm

Jorge Ramirez_4H wrote:How about elements in the third row?

Third row elements can have an expanded octet (up to 18 electrons, but they typically have 10-12)


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