Exceptions for the octet rule

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305086803
Posts: 99
Joined: Wed Sep 18, 2019 12:16 am

Exceptions for the octet rule

Postby 305086803 » Mon Nov 04, 2019 11:28 pm

Hi guys,

I saw that Br has the exceptions for the octet rule, allowing it to have more than 8 valence electrons because it is in period 4. What are any other exceptions I should know about?


Thanks!

Benjamin Feng 1B
Posts: 102
Joined: Sat Sep 07, 2019 12:19 am

Re: Exceptions for the octet rule

Postby Benjamin Feng 1B » Mon Nov 04, 2019 11:33 pm

Many of the elements with n is greater or equal to 3 can have an expanded octet, for example, chlorine and iodine. In addition, Boron and Aluminum sometimes do not have a complete octet and instead only have 6 valence electrons as it minimizes formal charge (ie BF3).

Rohit Ghosh 4F
Posts: 99
Joined: Thu Jul 25, 2019 12:17 am

Re: Exceptions for the octet rule

Postby Rohit Ghosh 4F » Thu Nov 07, 2019 4:14 pm

Also the first four elements can be seen as exceptions to the octet rule as they can be happy with either just a filled 1s shell, or in the case of hydrogen, it can just have no electrons.

Anthony Hatashita 4H
Posts: 103
Joined: Wed Sep 18, 2019 12:21 am

Re: Exceptions for the octet rule

Postby Anthony Hatashita 4H » Thu Nov 07, 2019 5:25 pm

Anything in the third period or past that because they have an empty d shell that can be expanded into

Emily_4B
Posts: 57
Joined: Wed Sep 18, 2019 12:21 am

Re: Exceptions for the octet rule

Postby Emily_4B » Thu Nov 07, 2019 6:43 pm

Benjamin Feng 4B wrote:Many of the elements with n is greater or equal to 3 can have an expanded octet, for example, chlorine and iodine. In addition, Boron and Aluminum sometimes do not have a complete octet and instead only have 6 valence electrons as it minimizes formal charge (ie BF3).

Why do Br and Al not need to have a full octet?

Daniel Martinez 1k
Posts: 50
Joined: Wed Sep 18, 2019 12:16 am

Re: Exceptions for the octet rule

Postby Daniel Martinez 1k » Thu Nov 07, 2019 6:46 pm

Sulfur is also an exception to the octet rule. I believe it can go up to 12 electrons as it does in SF6.


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