d and f BLOCK ELEMENTS

Why is Ce⁴⁺ able to form despite +3 being the common state?

• Its noble gas configuration provides extra stability
• It has a half-filled f-subshell
• It requires less energy to remove the fourth electron
• It is the most electronegative Lanthanoid

Which oxidation state is predominant for Lanthanoids in their compounds?

• +3
• +2
• +4
• +1

What is the trend observed in the ionic radii of M³⁺ ions of Lanthanoids as the atomic number increases?

• A fairly regular decrease
• An irregular increase
• A constant size
• An irregular zig-zag pattern

Which pair of elements is specifically mentioned as having almost identical atomic radii due to the lanthanoid contraction?

• Zr and Hf
• Sc and Y
• Ti and Zr
• La and Lu

What is a significant consequence of the lanthanoid contraction on the periodic table?

• It causes the radii of the third transition series elements to be very similar to those of the corresponding members of the second series
• It increases the reactivity of the first transition series
• It makes the Lanthanoids behave like alkali metals
• It eliminates the difference in properties between s-block and p-block elements