Question

Which of the following transition metal has the highest magnetic moment?

• A. $Sc^{3+}$
• B. $Ti^{3+}$
• C. $Cr^{2+}$
• D. $Fe^{2+}$
• E. $Mn^{2+}$

Hint:

$d^5$ configuration in a weak field always yields the maximum spin.

Answer 1

Answer: (E)

Step 1: Concept
Magnetic moment $\mu = \sqrt{n(n+2)}$ BM, where $n$ is the number of unpaired electrons.

Step 2: Meaning
Higher $n$ leads to a higher magnetic moment.

Step 3: Analysis
$Mn^{2+}$ has configuration $3d^5$ ($n=5$). $Fe^{2+}$ has $3d^6$ ($n=4$). $Cr^{2+}$ has $3d^4$ ($n=4$). $Sc^{3+}$ has $3d^0$ ($n=0$).

Step 4: Conclusion
$Mn^{2+}$ has the maximum unpaired electrons ($n=5$), hence the highest magnetic moment. Final Answer: (E)