The most common oxidation state for lanthanoids and actinoids is:

1. +5

2. -3

3. +1

4. +3

The different oxidation states exhibited by the lanthanoids are:

Lanthanoid's most common oxidation state is:
1. 2
2. 5 
3. 3 
4. 4

Which one of the following is a diamagnetic ion?

Actinoids show a greater number of oxidation states than lanthanoids because:  

The electronic configuration of the last element of actinoids is :

1. Thorium, Th: $\left[\mathrm{Rn}\right]5{\mathrm{f}}^{14}6{\mathrm{d}}^{1}7{\mathrm{s}}^2$

2. Lawrencium, Lr: $\left[\mathrm{Rn}\right]5{\mathrm{f}}^{14}6{\mathrm{d}}^{1}7{\mathrm{s}}^2$

3. Neptunium, Np: $\left[\mathrm{Rn}\right]5{\mathrm{f}}^{14}6{\mathrm{d}}^{1}7{\mathrm{s}}^2$

4. Protactinium, Pa: $\left[\mathrm{Rn}\right]5{\mathrm{f}}^{14}6{\mathrm{d}}^{1}7{\mathrm{s}}^2$

The incorrect statement among the following is: 

The correct statement regarding inner transition elements is

From the following, which is the most basic hydroxide?

1. Ce(OH)₃

2. Lu(OH)₃

3. Yb(OH)₃

4. Tb(OH)₃