The magnetic moment of Ni ²⁺ ion (atomic number of Ni =28 ) in BM unit is

Step-by-step solution

Ni ₂₈=[ Ar ]₁₈ 3 ~d ^8 4 ~s ^2, Ni ²⁺=[ Ar ]₁₈ 3 ~d ^8 4 ~s ^2 Number of unpaired electrons =2 Magnetic moment, = n(n+2) = 2(2+2) = 8 =2.84 BM