Which of the following molecules or ions utilize back bonding to stabilize their structure? — Chemical Bonding Chemistry Question

💡 Solution & Explanation

In $SO_2$, $PO_4^{3-}$, and $ClO_4^-$, the central atom (S, P, Cl) belongs to the 3rd period and uses its vacant $3d$ orbitals to accept electron density from the filled $2p$ orbitals of Oxygen, forming $p\pi-d\pi$ double bonds. $BF_3$ only has $2p$ orbitals available, restricting it to $p\pi-p\pi$ back bonding.