Chemistry - Complete d-block Question with Solution | TestHub

Question Explanation:

Calculate the ratio of exchange pairs in ${\mathrm{d}}^9$ and magnetic moment of Cr .

Concept:

Exchange pairs, magnetic moment formula.

Solution:

Part 1: Exchange pairs in d⁹

For d⁹, there are 5

↑

and 4

↓

electrons.

Pairs = ${}_5{C}_2{+}_4{C}_2=10+6=16$

Part 2: Magnetic moment of Cr

Cr configuration: $[Ar]3d^{5}4s^1$. n=6 unpaired electrons.

formula: $\mu =\sqrt{n(n+2)}$ BM.

$\mu =\sqrt{6(6+2)}=\sqrt{48}=4\sqrt{3}B.M.$ BM.

Part 3: Ratio

Ratio = = $\frac{16}{4\sqrt{3}}=\frac{4}{\sqrt{3}}$.

Final Answer: option (C)