According to the strict IUPAC definition of transition elements, which of the following statements a — d and f Block Elements Chemistry Question

💡 Solution & Explanation

A transition element must have partially filled $d$ -orbitals either in the neutral atom OR in any of its common stable oxidation states. While $Cu$, $Ag$, and $Au$ have $d^{10}$ in their ground state, their common ionized states (e.g., $Cu^{2+}$ is $d^9$, $Au^{3+}$ is $d^8$) have partially filled $d$ -orbitals, thus they are transition elements. $Zn$, $Cd$, $Hg$ maintain $d^{10}$ in their $+2$ states, so they are excluded. $Pd^{2+}$ is $4d^8$, making it a transition element despite its $4d^{10}$ ground state.