The low value for Sc reflects the stability of Sc³⁺, which possesses a noble gas configuration, highlighting the preference for achieving noble gas stability in its oxidation states.

The highest value for Zn is attributed to the removal of an electron from the stable d¹⁰ configuration of Zn²⁺, emphasizing the significance of achieving a fully filled d orbital for stability.

The comparatively high value for Mn signifies the stability of Mn²⁺(d⁵), while the comparatively low value for Fe highlights the extra stability associated with Fe³⁺(d⁵), showcasing the influence of electron configurations on oxidation state stability.

Cr and Cu show high second ionization enthalpies due to the removal of electrons from d orbitals, resulting in d⁵ and d¹⁰ configurations in M²⁺ ions, influencing their stability.

Fe²⁺ has a d⁶ configuration, while Mn²⁺ has a 3d⁵ configuration. The absence of exchange energy loss in the d⁶ configuration of Fe²⁺ results in lower ionization enthalpy compared to Mn²⁺, indicating that the third ionization enthalpy of Fe is ...