Which of the following has the highest spin-only magnetic moment value?

1. Ti3+

2. Mn2+

3. Fe2+

4. Co3+

HINTμ=n(n+2)BM

Explanation: Ion contains the maximum number of unpaired electrons has high magnetic moment values

Spin magnetic moment is√n(n+2), where n is the number of unpaired electrons. 

STEP 1: The configuration of ions are as follows:

Ti3+=Ar3d1
1unpairedelectron

Mn2+=Ar3d5
5unpairedelectron

Fe2+=Ar3d6
fourunpairedelectron

Co3+=Ar3d6
Fourunpairedelectron 

STEP 2:

The Mn2+ ion contains a maximum number of unpaired electrons, hence, it has a high spin-only magnetic moment value.