Expanded Valence Shells

[megan blatt 2B]

During lecture, Dr. Lavelle mentioned that the reason why atoms can accommodate more than 8 valence electrons is because they have d orbitals in the valence shell that accommodate additional electrons. Does this mean that any atom that has a energy level of 3 or higher on the periodic table can have an expanded octet? Otherwise, why do only some atoms like sulfur, phosphorous, and chlorine form expanded octets?

[Angela Grant 1D]

You are right about any atom with n=3 or higher being able to have an expanded valence shell. Dr. Lavelle mentioned that this applies to atoms in periods 3 and higher.

[LuisG14A1J]

Yes, it's possible for other atoms with energy level 3 and higher to have the expanded valence shells, but it's very unlikely because they are more stable with full octets/ it is "easier" for them to fill up with valence electrons or lose them to form a shared octet with a different atom. He noted that its most common for those in groups 13 and sometimes 14, but rarely, because they are sorta "in between" the stability of having 3, and 4 valence electrons. If they had more than 4 then it would be easier for them to gain 4 valence electrons to form a full octet than to lose 4. If they had 2 then it would be "easier" for them to lose 2 valence electrons to bond with atoms that then form a full octet for stability.
It might be possible to force hybrids to form but they wouldn't be stable as the energy required to make it possible would then be the same energy it could release from returning back to normal/ to a more stable bonding state.