Practice question

Given: Which of the following ions has a 3d⁸ configuration? These values define the system as per NCERT data. Formula: Ni (Z = 28): 3d⁸ 4s². This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Ni^{2+ : 3d⁸ (loses 2 from 4s). Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.