Chemistry - f-block Question with Solution | TestHub

Question Explanation:

Compare ionic sizes of ions.

Concept:

Lanthanide contraction & charge.

Solution:

* Higher positive charge and smaller atomic number lead to smaller ionic size.

* Ce⁴⁺ has a higher charge than La³⁺, so Ce⁴⁺ is smaller → option 1 is incorrect.

* Due to lanthanide contraction, La³⁺ is larger than Lu³⁺ → option 2 is incorrect.

* Ce³⁺ is larger than Lu³⁺ → option 3 is incorrect.

* Eu²⁺ has charge and larger size, while Yb³⁺ has a higher charge and smaller size → Eu²⁺ > Yb³⁺ is correct.

Final Answer: option (D)