Expanded valence shells

[AlyssaYeh_1B]

How come P, S, and Cl can accommodate more than 8 valence electrons? I don't understand how they can use d-orbitals to expand their shells

[chrisleung-2J]

It's not just P, S, and Cl that can exist with expanded valence shells. I believe that any element which has its valence electrons in the 3rd principal level or higher can accommodate more than 8 electrons, as it gains access to d-orbitals which first exist at the 3rd principal level and can be filled to form additional bonds or hold additional lone pairs for atoms of such elements

[KaitlynBali_4B]

I also read in the book that the size of the atom is another main factor that determines whether or not an atom can expand its valence shell or not. A potassium atom is capable of having five chlorine atoms bond to it, but a nitrogen atom is much smaller in size and cannot form this many bonds.

[SMIYAZAKI_1B]

When it comes to expanding the shells, it means that the electrons that should've gone to the new shell instead goes to the orbital's d-shell. For example, if the element is 3p5 and they have to accommodate 3 more electrons, they would bring them to 3d shell.