Out of the following, how many of them have magnetic moment value `sqrt(24)` BM.
` Ti^(2+) , Ti^(3+), V^(2+) , Cr^(2+) , Cr^(3+) . Mn^(2+) , Fe^(2+)`

Answer

2

Explanation

`Cr^(2+) , Fe^(2+)`
` Cr^(2+) (Z=24) , Cr = 3d^5 4s^1 implies Cr^(2+) = 3d^(4) 4s, mu = sqrt(4 (4+2))= sqrt(24) = 4.90`
` Fe^(2+) (Z=26 ), Fe= 3d^6 4s^2 implies Fe^(2+) = 3d^6 . 4s^0 , mu = sqrt(4(4+2))= sqrt(24)=4.90`