JEE MAIN - Chemistry (2008 - No. 20)
Larger number of oxidation states are exhibited by the actinoids than those by the lanthanoids, the
main reason being :
4f orbitals more diffused than the 5f orbitals
lesser energy difference between 5f and 6d than between 4f and 5d orbitals
more energy difference between 5f and 6d than between 4f and 5d orbitals
more reactive nature of the actinoids than the lanthanoids
Forklaring
NOTE : The main reason for exhibiting larger number of oxidation states by actinoids as compared to lanthanoids is lesser energy difference between $$5f$$ and $$6d$$ orbitals as compared to that between $$4f$$ and $$5d$$ orbitals.