Which of the following orders regarding atomic or ionic sizes are experimentally CORRECT? — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Order A is correct due to transition contraction (poor shielding of 10 $3d$ electrons making Ga shrink). Order B correctly lists an isoelectronic series where size decreases as $Z$ increases. Order D is correct due to lanthanide contraction affecting the 4d and 5d series similarly. Order C is incorrect because a higher positive oxidation state means fewer electrons, pulling the remaining ones closer ($Cr^{6+}$ is smaller than $Cr^{3+}$).