Q. Four successive members of the first row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionization enthalpy ?
A) Vanadium (Z = 23)
B) Chromium (Z = 24)
C) Iron (Z = 26)
D) Manganese (Z = 25)
Explanation
[Solution from source] The third electron of Mn is removed from Mn²⁺ (3d⁵), a stable half-filled configuration, so Mn has the highest third ionisation enthalpy. For Fe, removal from 3d⁶ gives the stable 3d⁵, so it is easier. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.