JEE Main 2024 Chemistry question
Which one of the following complexes will exhibit the least paramagnetic behaviour? [Atomic number, Cr = 24, Mn = 25, Fe = 26, Co = 27]
Answer: (A)
Solution
With the weak-field ligand H₂O the unpaired electrons are: Co²⁺ (d⁷) 3, Fe²⁺ (d⁶) 4, Mn²⁺ (d⁵) 5, Cr²⁺ (d⁴) 4.