Question

Transition metals and many of their compounds show paramagnetic behaviour where there are unpaired electron or electrons. The magnetic moment arises from the spin and orbital motions in ions or molecule. Magnetic moment of n unpaired electrons is given as
`mu=sqrt(n(n+2))` Bohr magneton
Magnetic moment increases as the number of unpaired electrons increases.
Q. Which among the following ions has maximum value of magnetic moment
A. `Cu^(2+)`
B. `Mn^(2+)`
C. `Cr^(2+)`
D. `Ti^(2+)`

Answer 1

Correct Answer - b
`Mn(Z=25)implies3d^54s^2`
`Mn^(2+)=3d^5(n=5)mu=sqrt(35)BM`
`Cr(Z=24)implies3d^54s^1`
`Cr^(2+)=3d^4(n=4)mu=sqrt(24)BM`
`Ti(Z=22)implies3d^24s^2`
`Ti^(2+)=3d^2(n=2),mu=sqrt8BM`