The calculated spin only magnetic moment of Cr ²⁺ ion is

Step-by-step solution

The atomic number of Chromium (Cr) is 24 . The electronic configuration of Cr atom is [ Ar ] 3d⁵ 4s¹ . For Cr ²⁺ ion, two electrons are removed, giving the configuration [ Ar ] 3d⁴ . The number of unpaired electrons ( n ) in Cr ²⁺ is 4 . The spin only magnetic moment ( ) is calculated using the formula: = n(n+2) BM Substituting n = 4 : = 4(4+2) = 24 4.90 BM Answer: 4.90 BM