Expanded Octets

[Malik Oda 1F]

How do I identify an expanded octet and how would I approach drawing the Lewis Structure?

[SGonzales_3L]

One rule of thumb is to calculate the number of valence electrons in a molecule. Fulfill the octet rule for every atom in the Lewis structure. If you still have some electrons left over, it is highly likely that there is an atom with an expanded octet. Usually elements in the p-block, in period 3 or higher can accommodate expanded octets. Thus, add lone pairs of electrons to those atoms within a molecule and as always, calculate the formal charge.

[Brooke Yasuda 2J]

Most of the time when you have a molecule that can form an expanded octet, such as Xenon, you know that it has eight valance electrons. In bonding, you're trying to reduce formal charge, so you can form double bonds between Xenon and other atoms to reduce the formal charge as much as possible.

[Robert Tran 1B]

Expanded octets would be used if it's clear that there is more than 4 atoms bonded to the central atom (ex: XeF5). Also, the octet can be expanded if the formal charge favors it in the lewis structure.

[thanh24mai]

You may sometimes need to expand an octet if you want to ensure you have drawn the most stable lewis structure.

[LBacker_2E]

Overall, if an expanded octet can be formed (is past 2p orbitals) to yield lower formal charges on the central atom, will this always be a more stable structure?

[Doreen Liu 4D]

For some elements, expanded octets are not allowed (i.e. some period 2 elements), so just be careful when you're drawing those.