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

Which one of the following sets correctly represents the increase in the paramagnetic property of the ions?
  1. $\mathrm{Cu}^{2+}>\mathrm{V}^{2+}>\mathrm{Cr}^{2+}>\mathrm{Mn}^{2+}$
  2. $\mathrm{Cu}^{2+} < \mathrm{Cr}^{2+} < \mathrm{V}^{2+} < \mathrm{Mn}^{2+}$
  3. $\mathrm{Cu}^{2+} < \mathrm{V}^{2+} < \mathrm{Cr}^{2+} < \mathrm{Mn}^{2+}$
  4. $\mathrm{V}^{2+} < \mathrm{Cu}^{2+} < \mathrm{Cr}^{2+} < \mathrm{Mn}^{2+}$

Solution

Paramagnetic property depends upon the number of unpaired electrons. Higher the number of unpaired electrons, higher the paramagnetic property will be. $\mathrm{Cu}^{2+}=[\mathrm{Ar}] 3 d^9 \text {, no. of unpaired electrons }=1$ $\mathrm{V}^{2+}=[\mathrm{Ar}] 3 d^3$, no. of unpaired electrons $=3$ $\mathrm{Cr}^{2+}=[\mathrm{Ar}] 3 d^4$, no. of unpaired electrons $=4$ $\mathrm{Mn}^{2+}=[\mathrm{Ar}] 3 d^5$, no. of unpaired electrons $=5$ Hence, correct order is $\mathrm{Cu}^{2+} < \mathrm{V}^{2+} < \mathrm{Cr}^{2+} < \mathrm{Mn}^{2+}$

Asked in: AP EAMCET 2009

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