Which of the following pair of ions have same paramagnetic moment?

• Correct answer
  A

  $\mathrm{Cu}^{2+}, \mathrm{Ti}^{3+}$
• B

  $\mathrm{Mn}^{2+}, \mathrm{Cu}^{2+}$
• C

  $\mathrm{Ti}^{4+}, \mathrm{Cu}^{2+}$
• D

  $\mathrm{Ti}^{3+}, \mathrm{Ni}^{2+}$

Solution

${ }_{29} \mathrm{Cu}=[\mathrm{Ar}] 3 d^{10} 4 s^1$
Both of these ions have one unpaired electron, hence these have same paramagnetic moment.

Hence, the correct answer is option: 'A'.