As a direct chemical consequence of the Lanthanide Contraction, the basic character of the lanthanoi — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Due to the contraction, the ionic radius of $Ln^{3+}$ cations strictly decreases from $La$ to $Lu$. As the cation shrinks, its polarizing power increases. Per Fajan's rules, this increases the covalent character of the $Ln-OH$ bond, making it harder to dissociate in water, thereby decreasing basicity.