KCET 2026 Chemistry Solved Paper

Concept:The position of an element in the periodic table is determined from its electronic configuration, especially the highest occupied shell and valence electron count.Explanation:For Ra ($Z=88$), configuration is $[\mathrm{Rn}]\,7s^{2}$. Highest shell is 7, valence electrons in $s$ are 2, so it lies in $7^{\text{th}}$ period and $2^{\text{nd}}$ group. Thus, Ra → (iv).For Ga ($Z=31$), configuration is $[\mathrm{Ar}]\,3d^{10}\,4s^{2}\,4p^{1}$. Highest shell is 4, and the outer configuration $ns^{2}np^{1}$ places it in $4^{\text{th}}$ period and $13^{\text{th}}$ group. Thus, Ga → (i).For W ($Z=74$), it is tungsten, a transition metal located in $6^{\text{th}}$ period and $6^{\text{th}}$ group. Thus, W → (ii).For Pd ($Z=46$), it is palladium, also a transition metal, located in $5^{\text{th}}$ period and $10^{\text{th}}$ group. Thus, Pd → (iii).Combining these matches gives: a-iv, b-i, c-ii, d-iii.Answer:The correct option is A: a-iv, b-i, c-ii, d-iii.