Arrange the following metal complex/ compounds in the increasing order of spin only magnetic moment. Presume all the three, high spin system. (Atomic numbers Ce = 58 , Gd = 64 and Eu = 63 .) (a) NH 4 2 Ce NO 3 6 (b) Gd NO 3 3 and (c) Eu NO 3 3

Step-by-step solution

(a) Ce 58 → Xe 4 f 2 5   d 0 6   s 2 In complex Ce 4 + → Xe 4 f 0 5   d 0 6   s 0 there is no unpaired electron so μ m = 0 (b) Gd 64 3 + → Xe 4 f 7 5   d 0 6   s 0 contain seven unpaired electrons so, μ m = 7 7 + 2 = 63   B . M . (c) Eu 63 3 + → Xe 54 4 f 6 5 d 0 6 s 0 contain six unpaired electron so, μ m = 6 6 + 2 = 48   B . M . Hence, order of spin only magnetic movement b > c > a