Q. Which of the following pairs has the same size?
A) Zn²⁺, Hf⁴⁺
B) Fe²⁺, Ni²⁺
C) Zr⁴⁺, Ti⁴⁺
D) Zr⁴⁺, Hf⁴⁺
Explanation
[Solution from source] Because of the lanthanoid contraction, Hf (5d) is almost the same size as Zr (4d), so Zr⁴⁺ and Hf⁴⁺ have nearly identical radii. Ti⁴⁺ is a 3d ion and clearly smaller than Zr⁴⁺. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.