Question

Which one of the following sets correctly represents the increase in the paramagnetic property of the ions?

• A. \(Cu^{2+}>V^{2+}>Cr^{2+}>Mn^{2+}\)
• B. \(Cu^{2+}<Cr^{2+}<V^{2+}<Mn^{2+}\)
• C. \(Cu^{2+}<V^{2+}<Cr^{2+}<Mn^{2+}\)
• D. \(V^{2+}<Cu^{2+}<Cr^{2+}<Mn^{2+}\)

Hint:

Paramagnetism increases with number of unpaired electrons. Count unpaired electrons in \(d\)-subshell to compare ions.

Answer 1

The Correct Option is C

Step 1: Paramagnetism depends on unpaired electrons.
More unpaired electrons \(\Rightarrow\) more paramagnetic.
Step 2: Find electron configurations.
\[ Cu^{2+} : [Ar]\,3d^9 \Rightarrow 1 \text{ unpaired} \]
\[ V^{2+} : [Ar]\,3d^3 \Rightarrow 3 \text{ unpaired} \]
\[ Cr^{2+} : [Ar]\,3d^4 \Rightarrow 4 \text{ unpaired} \]
\[ Mn^{2+} : [Ar]\,3d^5 \Rightarrow 5 \text{ unpaired} \]
Step 3: Arrange increasing order.
\[ Cu^{2+} (1)<V^{2+} (3)<Cr^{2+} (4)<Mn^{2+} (5) \]
Final Answer:
\[ \boxed{Cu^{2+}<V^{2+}<Cr^{2+}<Mn^{2+}} \]