Lanthanoids project 3 different oxidation states which are +2, +3, +4. Among these, the +3 oxidation state is the most common. Lanthanoids exhibit a limited number of oxidation states because of the large energy difference between 4f, 5d, and 6s orbitals. While, the energy difference between 5f, 6d, and 7s orbitals is very less. Hence, actinoids display a large number of oxidation states.

For example, neptunium displays +3, +4, +5, and +7 while uranium and plutonium display +3, +4, +5, and +6 oxidation states. The most common oxidation state in case of actinoids is also +3.