Octet exceptions

[1K Kevin]

Hi,
Elements that are in period 3 and up can have expanded shells that hold more than 8 but will they always have more or when can they?

[Ibrahim Malik 1H]

S, P, Si, and Cl are common elements that can form an octet because they can utilize the d-orbital found in the 3rd energy level. Elements generally will only want to fill their octet and only go over and expand their octet if they have to, with these 4 elements being able to have an expanded octet.

[Brian Chang 2H]

Technically any element in the 3rd row and beyond has access to their d-orbitals, but we only really see elements in group 15,16, and 17 do this because it's highly unlikely for elements like Boron, Aluminium, or Gallium to ever have an expanded octet.

Cheers.

[Lia Inadomi 1I]

Why can they have expanded shells?

[Minsub Lee 3E]

They can have expanded valence shells because they have d-orbitals to accommodate additional electrons.

[EllaBerry]

Elements in period three can, but don't always have to, have an expanded octet. Usually just P, Cl, and S will in that period.

[yuetao4k]

Elements that are past the 3rd period can have an expanded octet, but it depends on what the compound is to determine whether or not it needs to use an expanded octet.

[Matthew Choi 2H]

If you look at the principal levels: the 1st principal level only has an s sublevel, the 2nd has an s and a p sublevel, and the 3rd has an s, p, and d sublevel. In order to achieve more than an octet, an atom must have access to the d sublevel in order to go past their octet. This is why atoms in the 3rd principal level and beyond are the only ones that can do this.

[Ethan Breaux 2F]

In all honesty, the octet rule is pretty worthless after the few elements in the 2nd row that it applies to. We just pretend that it continues but hardly anyone knows anything about any element after the 3rd row.