Expanded Valence

[Emma Ide 2E]

Hi, I'm confused about when an atom can have an expanded valence shell. I was adding up the number of valence electrons and then drawing a Lewis structure, but I had 2 electrons left over and was wondering if this was a case of expanded valence?

[SavannahScriven_1F]

Expanded valence shells can begin starting with the p block in row 3. (because once you get to n=3, l can be 0, 1, or 2 and l=2 is a d orbital. The d orbital has the capacity to hold more electrons). After the p block in row 3, I'm pretty sure any element can theoretically have an expanded shell (except for those elements in groups 1 and 2). So in short, elements that have d orbitals have the ability to form more than an octet. The octet guidelines comes from the 2 electrons in an s orbital and the 6 electrons in the 3 p orbitals. When d orbitals are present, electrons can go into these if it leads to a more stable structure.

[Selena Quispe 2I]

Expanded octets can only happen on elements in period 3 and up so if you the central atom of the lewis structure you are drawing is in period 3 or period 4, etc then it could have an expanded octet! I hope this helps :)

[Lung Sheng Liang 3J]

You can have expanded valence only in elements that reside in period 3 or up and they have to be p-block elements.

[Julianna Shimabukuro 1D]

As the others said, it is the elements in group 3 and above, so groups 3, 4, 5, and so on. Common examples of these are sulfur, phosphorus, and chlorine.

[Carolina Gomez 2G]

Elements can have an expanded valence if they are in period 3 and above that have the d-block orbitals.

[allyssa bradley 1H]

For the expanded valence shell, does this then mean that the maximum expanded valence shell is 10 or 12 (or more, if the atom has a negative charge)? I'm a little confused since the normal valence is 2 in s and 6 in p, but 12+ seems like a lot in the outer shell.

[James Patanian 2C]

For the expanded valence shell, does this then mean that the maximum expanded valence shell is 10 or 12 (or more, if the atom has a negative charge)? I'm a little confused since the normal valence is 2 in s and 6 in p, but 12+ seems like a lot in the outer shell.

I think the most normal examples are with 10 from the example compounds that I’ve seen. Regardless, if the formal charges are better with an expanded octet, that will probably be one of the resonance structures.

[Isabella Cortes 2H]

An atom can have an expanded octet if it is in row 3 or below so if you are drawing lewis structures and you have leftover electrons, then they may belong to an atom with an expanded octet.

[MichaelRaad_1F]

An atom can have an expanded valence if it has space in the d orbital. Elements period 3 and below can have expanded valence shells.

[Bai Rong Lin 2K]

Hi, I'm confused about when an atom can have an expanded valence shell. I was adding up the number of valence electrons and then drawing a Lewis structure, but I had 2 electrons left over and was wondering if this was a case of expanded valence?

It revolves with period 3 and p block elements

[Aydin Karatas 1F]

Expanded octets can occur in p-block elements in row 3 or below. This is because they have an unoccupied d-orbital that can accept more elections than the conventional octet rule. The most common ones you'll see are Sulfur, Phosphorus, and Chlorine.