Observe the variation of atomic radii in the transition series as atomic number increases from to . — d and f Block Elements Chemistry Question

💡 Solution & Explanation

The atomic radius decreases from $Sc$ to $Cr$ because the effective nuclear charge increases and the shielding effect of the few $d$ -electrons is weak. From $Mn$ to $Ni$, the increased shielding effect of the added $d$ -electrons counterbalances the increased nuclear charge, keeping the radius nearly constant. Towards the end ($Cu$ and $Zn$), electron-electron repulsion in the highly populated $d$ -orbitals dominates, causing a slight increase in radius.