Question

Actinoids exhibit greater range of oxidation states than lanthanoids.WHY ?

Answer 1

Actinides exhibits larger oxidation states than lanthanide because of very small energy gap between 5f, 6d and 7s subshells . The energies are decided on the basis of (n+l) rule. The (n+l) values of the tree orbitals are as under:

5 f = 5 + 3 = 8

6 d = 6 + 2 = 8

7 s = 7 + 1 = 8

All of the values comes out to be same . Hence they have same energy.