A dipositive transition metal ion with atomic number 25 in aqueous solution; what is the magnetic moment of it?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 5.92 BM
Atomic number 25 corresponds to Manganese (Mn).
A dipositive ion Mn²⁺ has:
- Atomic number = 25
- Electronic configuration of Mn = [Ar] 3d⁵ 4s²
- For Mn²⁺ → remove two 4s electrons → 3d⁵
Thus, Mn²⁺ has 5 unpaired electrons.
Magnetic moment formula:
$\mu = \sqrt{n(n+2)} \text{ BM}$
where n = number of unpaired electrons = 5
$\mu = \sqrt{5(5+2)} = \sqrt{35} = 5.92 \text{ BM}$