Considering `H_2O` as a weak field ligand, the number of unpaired electrons in `[Mn(H_2O)_6]^(2+)` will be (At. no. of `Mn=25`)

Options

A. three
B. five
C. two
D. four

Answer

B

Explanation

In ` [Mn (H_(2)O)_(6)]^(2+)` mn is present as `mn^(2+)` mn (II) so its electronic congfiguration `= 1s^(2 ) , 2s^(2)2p^(6) ,3s^(6) 3p ^(6) 3d^(5)`

in `[Mn (H_(2) O)_(6) ]^(2+)` the coordination number of Mn is six , but in the presence of weak field ligand there will be no pairing of electrons in 3d .SO it well form high spin complex .It contains five unpaired electrons .
in `[Mn (H_(2)O)_(6)]^(2+)`