Which of the following pair of transition metal ions, have the same calculated values of magnetic moment?
Which of the following pair of transition metal ions, have the same calculated values of magnetic moment?
$\mathrm{Ti}^{2+}$ and $\mathrm{V}^{2+}$
$\mathrm{Fe}^{2+}$ and $\mathrm{Cu}^{2+}$
$\mathrm{Cr}^{2+}$ and $\mathrm{Fe}^{2+}$
$\mathrm{Co}^{2+}$ and $\mathrm{Ti}^{2+}$
Solution
$\mathrm{Cr}^{2+}(Z=24):[\mathrm{Ar}] 3 d^4 4 s^0 ; \quad 4 \quad$ unpaired electrons $\quad \mathrm{Fe}^{2+}(Z=26):[\mathrm{Ar}] 3 d^6 4 s^0$; 4 unpaired electrons $\mathrm{Cr}^{2+}$ and $\mathrm{Fe}^{2+}$ have same number of unpaired electrons, hence they have the same value of magnetic moment.