octet exceptions

[Kristy 1F]

Is there any reason for the octet exceptions that elements in 13th column don’t have to complete octet？

[julia_lok_2K]

I don't think the textbook explains this exception, and I tried looking it up on other websites as well but they didn't really explain it either, and Lavelle didn't give a reason too. So my guess is that you only have to memorize this exception and won't have to explain this trend on the exam.

Sorry if this wasn't much help to you

[zoepamonag4C]

I think that it's because elements (ex:Cl, S, etc) that are able to have expanded octets can use the 3d subshell.

[daisyjimenezt]

they can have d states which allows for an expanded octet

[Alexandra Ortega 4D]

Elements in the 13th column do not form octets because they are simply more stable with less than 8 valence electrons, such as boron which only forms 3 bonds. Boron only has 3 valence electrons to begin with, so it does not have enough electrons to form more than 3 covalent bonds.