The oxidation state is the universally dominant and most stable state for all lanthanoids. However, — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Although $Ce^{4+}$ achieves stability by possessing an empty $4f^0$ core, the overarching thermodynamic hydration stability of the entire series strictly favors $+3$. Therefore, $Ce^{4+}$ has an immense drive to capture an electron and become $Ce^{3+}$, acting as an aggressive oxidizing agent.