Which of the following statements regarding atomic and ionic radii are CORRECT? — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

A cation has fewer electrons but the same protons, pulling the remaining electrons tighter. $4d$ and $5d$ radii are similar due to the poor shielding of $4f$ electrons (Lanthanide contraction). Anions are larger because added electrons increase repulsion. Statement D is incorrect because Noble gases are measured by their Van der Waals radii, making them the largest in their respective periods.