Lanthanoid primarily shows three oxidation states +2, +3, and +4 and out of these +3 is most common in lanthanoids. they show limited no. of oxidation states due to the large difference in energies of 4, 5 and 6 orbitals. But, actinoids shows large no. of oxidation state because they have comparable energy difference in 5,6 and 7 orbitals. For example and exhibits +3, +4, +5 and +6 oxidation states.