Which of the following metal ions has a calculated magnetic moment value of `sqrt(24)` BM ?

Options

A. `Mn^(2+)`
B. `Fe^(2+)`
C. `Fe^(3+)`
D. `Co^(2+)`

Answer

b

Explanation

We know that, magnetic moment `(mu)` is related to number ofunparied electron n, as `mu_(eff) = sqrt(n (n + 2)) BM`
`mu_(eff) = sqrt(24) BM`
This corresponcs, `n = 4` as `mu_(eff) = sqrt(4 (4 + 1)) = sqrt(24)`
`= 2. sqrt(2). Sqrt(3)`
`= 2 xx 1.414 xx 1.732`
= 4.89 Bm
(Trick) = Number of unpaired `e^(-)` are equal to value of variable number of BM)
Out of given option, `Fe^(2+)` has 4 unparied electrons as
`Fe^(2+) = [Ar] =`