The chemistry of the actinoid elements is not so smooth as that of the lanthanoids. Justify this statement by giving some examples from the oxidation state of these elements.

Explanation

Lanthanoids show (+2), (+3) and (+4) oxidation states. However (+3) oxidation state is most dominant. Actinoid shows oxidation states ranging from (+3) to (+7). The large range of oxidation states of actinoides as compared to lanthanoids is because of comparable energies of 5f, 6d and 7s orbitals. For example, the maximum oxidation state increases from (+4) in Th to (+5), (+6) and (+7) respectively in Pa, U and Np but decreases in succeeding elements. However (+3) and (+4) ions tend to hydrolyze. Hence, it is unsatisfactory to review the chemistry of actinoids in terms on oxidation states.