Expanded Octet

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Gabriella Bates 2L
Posts: 113
Joined: Thu Jul 11, 2019 12:15 am

Expanded Octet

Postby Gabriella Bates 2L » Sun Oct 27, 2019 11:40 am

Can someone please explain why certain elements can have an expanded octet?

Jonathan Gong 2H
Posts: 105
Joined: Sat Jul 20, 2019 12:16 am

Re: Expanded Octet

Postby Jonathan Gong 2H » Sun Oct 27, 2019 12:09 pm

Elements/atoms in period 3 or higher have a d-orbital in their valence shell, allowing them to accommodate more than 8e-. For example, P, S, and Cl. Hope this helps.

Aarushi Solanki 4F
Posts: 107
Joined: Sat Jul 20, 2019 12:17 am

Re: Expanded Octet

Postby Aarushi Solanki 4F » Sun Oct 27, 2019 12:29 pm

An atom (ex: P, S) is said to have an expanded valence shell if it has more than an octet (8 valence electrons). This is only possible when the valence shell has enough orbitals to "make space" for the extra electrons.

Matt F
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

Re: Expanded Octet

Postby Matt F » Sun Oct 27, 2019 12:51 pm

In class I remember Phosphorus, Sulfur, and Chlorine being given as examples. Are other elements beyond these 3 capable of having an expanded octet. I have written in my notes that atoms in Period 3 or higher have d-orbitals in valence shells that accommodate additional electrons, so does that apply to other elements aside from the ones I mentioned?

Nuoya Jiang
Posts: 99
Joined: Sat Sep 14, 2019 12:17 am

Re: Expanded Octet

Postby Nuoya Jiang » Sun Oct 27, 2019 12:57 pm

Elements that have d-orbitals are able to fit more than 8 valence electrons, so they can expand the Octet.

Amy Xiao 1I
Posts: 101
Joined: Sat Jul 20, 2019 12:15 am

Re: Expanded Octet

Postby Amy Xiao 1I » Sun Oct 27, 2019 1:44 pm

If that is the case, why even have the Octet rule? I understand that it is an easy rule of thumb for many elements, but if it does not really apply after the d-orbital comes into play, is it really helpful?

Posts: 109
Joined: Wed Sep 18, 2019 12:21 am

Re: Expanded Octet

Postby 205154661_Dis2J » Sun Oct 27, 2019 2:20 pm

It is stated that d-orbitals can carry more than 8e-. The examples that Dr. Lavelle gave in lecture were the elements, Chlorine, Phosphorus and Sulfur.

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