JEE Main Chemistry Question (2026) — Solution

Step-by-step solution

In an octahedral complex, the d-orbitals split into t_ 2g and e_g levels. For d^3: Configuration is t_ 2g ^3 e_g^0. Number of unpaired electrons = 3. For d^4 (low spin): Configuration is t_ 2g ^4 e_g^0. Number of unpaired electrons = 2. For d^5 (high spin): Configuration is t_ 2g ^3 e_g^2. Number of unpaired electrons = 5. For d^6 (high spin): Configuration is t_ 2g ^4 e_g^2. Number of unpaired electrons = 4. For d^7 (low spin): Configuration is t_ 2g ^6 e_g^1. Number of unpaired electrons = 1. Total number of unpaired electrons = 3 + 2 + 5 + 4 + 1 = 15. Answer: 15