Question

The d-electron configurations of `Cr^(2+), Mn^(2+), Fe^(2+)` and `Co^(2+)` are `d^4, d^5, d^6` and `d^7` respectively. Which one of the following will exhibit minimum paramagnetic behavious?
A. `[Fe(H_(2)O)_(6)]^(2+)`
B. `[Co(H_(2)O)_(6)]^(2+)`
C. `[Cr(H_(2)O)_(6)]^(2+)`
D. `[Mn(H_(2)O)_(6)]^(2+)`

Answer 1

Correct Answer - B

`therefore [Co(H_(2)O)_(6)]^(2+)` has minimum number of unpaired electrons and thus, shows miniumum paramagnetic behaviour.
Higher the unpaired `e^(-)`.
Higher the magnetic moment
`mu = sqrt(n(n+2))`
n=Number of unpaired `e^(-)`