First three ionisation energies (in kJ/mol) of three representative elements are given below : Eleme — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Understand that the magnetic moment is directly proportional to the number of unpaired electrons in d-block elements. Step 2: As atomic number (Z) increases within a transition series, the number of unpaired electrons first increases from 1 to 5 (or 6), and then decreases as pairing begins, eventually reaching 0. Step 3: This rise to a peak and subsequent fall is represented by the parabolic/dome-shaped graph in option (d).