Transition elements show magnetic moment due to spin and orbital motion of electrons. Which of the following metallic ions have almost same spin only magnetic moment?

Options

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

Answer

A, D

Explanation

Electronic configuration of `Co^(2+) = [Ar]3d^(7)`, Number of unpaired electrons = 3
Electronic configuration of `Cr^(2+) = [Ar]3d^(4)`, Number of unpaired electrons = 4
Electronic configuration of `Mn^(2+) = [Ar] 3d^(5)`, Number of unpaired electrons = 5
Electronic configuration of `Cr^(3+) = [Ar] 3d^(3)`, Number of unpaired electrons = 3
Hence, it is clearly seen that both `Co^(2+)` and `Cr^(3+)` have same number of unpaired electrons. i.e., 3.