Calculate the magnetic moment (spin-only) of a trivalent ion in aqueous solution if its atomic number is 22.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 1.73 BM
Atomic number 22 → Titanium (Ti)
Electronic configuration of Ti:
$\text{Ti} = [Ar]\,3d^2\,4s^2$
For Ti³⁺ (trivalent ion): three electrons are removed.
- Loses 2 electrons from 4s and 1 from 3d
$\text{Ti}^{3+} = [Ar]\,3d^1$
So, number of unpaired electrons:
$n = 1$
Spin-only magnetic moment:
$\mu = \sqrt{n(n+2)} = \sqrt{1(1+2)} = \sqrt{3} \approx 1.73 \text{ BM}$