In context of the lanthanoids, which of the following statements is not correct? — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: The +3 oxidation state is the most common and stable oxidation state for all lanthanoids. Step 2: Some lanthanoids exhibit +2 and +4 oxidation states in addition to +3 due to the extra stability of empty (f0), half-filled (f7), or fully filled (f14) f-subshells (e.g., Ce4+ has f0, Tb4+ has f7). However, not all members of the lanthanoid series can form stable +4 compounds. Step 3: Stating that +4 compounds are formed by all members of the series is incorrect, which corresponds to option (a).