General Properties of Actinides:-

1. Oxidation State of Actinides:- Unlike Lanthanoids, Actinioids show a variable of O.S. It is because of decreased energy gap between 5f, 6d & 7s sub shells. Hence all electrons can it they also show +2, +4 +5, +6 oxidation states also.
2. Atomic size (Actinoid contraction):- The atomic size of the actinoids goes on decreasing along the series like lanthanoids. This is called actinoid contraction. The cause of Actinoid Contraction is the poor shielding effect produced by 5f- electrons.

The actinoid contraction is more pronounced than Lanthnoid Contraction Because 5f-orbitals are extended beyond 6s and 6p orbitals in space, but 4f-orbitals are buried deep inside the atom. Hence shielding effect produced by 5f-orbitals is less than 4f-orbitals and size decreases to a larger extent.

Uses of Actinides:-

1. Uranium is used as nuclear fuel and in medicines.
2. Thorium is used in nuclear reactor and in treatment of cancer.
3. Plutonium is used in nuclear reactor and in making fusion materials.

Difference between Lanthanides and Actinides:

Lanthanides	Actinides
Beside +3 oxidation state they also show +2 and +4 oxidation states.	Besides +3 oxidation state they show +2, +4, +5 and +6 oxidation state.
Lanthanides (except Promethium) are Non Radio Active	Actinides are Radio Active.
They have fewer tendencies to complex formation.	They have greater tendency  towards complex formation.
Lanthanoid compounds are less basic.	Actinoid compounds are more basic.