expanded octet in d orbital

[Hazelle Gunawan 3G]

can someone explain how elements with a d orbital have an expanded octet? i'm a little confused on how that translates to the overall placement of electrons

[Brennan McGurrr 3C]

P-block elements with a principal quantum number (n) of 3 or more have electrons in d orbitals. In normal octet bonding, only the s and p orbitals are being shared, which is why each element is most stable with 8 valence electrons. However, to accomodate formal charge, electrons in the d orbitals can become involved in bonding to make the bonded elements more stable. These elements can form more than 4 bonds due to their electrons in d orbitals.

[Samudrala_Vaishnavi 3A]

So elements with an expanded orbital, meaning that they could potentially hold more electrons in a Lewis structure, has to do with the fact that the d-orbital allows for extra space of up to 10 valence electrons. Looking at the periodic table, we see that elements that are before Period 3 tend to have gaps where the d-block is so they can only hold up to 7 valence electrons. We would just calculate the number of valence electrons like you would for a Lewis structure before Period 3, but you will notice that they are more electron pairs that are needed, so you can add more lone pairs to the central atom.

[sophie esherick 3H]

Only P block atoms with a principal quantum number of 3 or more can have electrons in d orbitals.This is because their azimuthal quantum number can be 2 which corresponds to a d subshell. In a normal octet, only the s and p orbitals are being filled, which is why each element is most stable with 8 valence electrons. With octet bonding, only the valence electrons in the s and p shells are shared which is why we use the octet guideline. However, to lower formal charge and create an overall more stable structure, an atom can potentially hold more than 8 electrons because it had an empty d orbital. This means that more bonds can be made. Hope this helps!

[simona_krasnegor_1C]

The d-orbtial has extra space (for 10 electrons), so when an element has this orbital, it is more likely to have an expanded octet.