Question

[Cr(H₂O)₆]Cl₃ (at. no. of Cr = 24) has a magnetic moment of
3.83 B. M. The correct distribution of 3d electrons in the
Chromium of the complex is
(a) 3dₓᵧ¹, (3dₓ²₋ᵧ²)¹, 3dyz¹
(b) 3dₓᵧ¹, 3dyz¹, 3dxz¹
(c) 3dₓᵧ¹, 3dyz¹, 3dz¹
(d) (3dₓ²₋ᵧ²)¹, 3dz², 3dₓᵧ¹

Answer 1

The correct distribution of 3d electrons in the  Chromium of the complex [Cr(H₂O)₆]Cl₃ is : 3dₓᵧ¹, 3dyz¹, 3dxz¹

- magnetic moment given is 3.83

- putting this is formula, we get

$\sqrt{n(n+2)}$ = 3.83

              n = 3

- so the no. of unpaired electrons is 3

- here, Chromium is in +3 oxidation state

- this means its outer electronic configuration is 3$d^{3}$

- thus these 3 unpaired electrons are in the t2g level of 3d orbital, i.e., 3dₓᵧ¹, 3dyz¹, 3dxz¹

- so the correct option is (b)