The common oxidation states associated with cerium (Ce) are:

1. +3 , +4 

2. +2, +3 

3. +2, +4 

4. +3, +5 

Ce³⁺ , La³⁺ , Pm³⁺ and Yb³⁺  have ionic radii in the increasing order as: 

1. La³⁺ < Ce³⁺ < Pm³⁺ < Yb³⁺

2. Yb³⁺ < Pm³⁺ < Ce³⁺ < La³⁺

3. La³⁺ = Ce³⁺ < Pm³⁺ < Yb³⁺  

4. Yb³⁺ < Pm³⁺ < La³⁺ < Ce³⁺

Which of the following groups of transition metals is called coinage metals?

1. Cu , Ag, Au

2. Ru , Rh, Pd

3. Fe , Co , Ni

4. Os , Ir , Pt

The radius of La³⁺ (Atomic number of La =57) is 1.06 Å. Which one of the following given values will be closest to the radius of Lu³⁺ (Atomic number of Lu = 71)?

Which of the following explains the primary cause of lanthanoid contraction?