Question

In a borax bead test under hot condition, a metal salt (one from the given) is heated at point B of the flame, resulted in green colour salt bead. The spin-only magnetic moment value of the salt is ............. BM (Nearest integer)
[Given atomic number of Cu = 29, Ni = 28,Mn = 25, Fe = 26]

Answer 1

Correct Answer: 6

The green bead indicates the presence of Fe³⁺. The number of unpaired electrons in Fe³⁺ is 5. The spin-only magnetic moment is given by:

\( \mu = \sqrt{n(n + 2)} \, \text{BM} \)

Substituting \( n = 5 \):

\( \mu = \sqrt{5(5 + 2)} = \sqrt{35} \approx 5.92 \, \text{BM} \)

Nearest integer = 6.