Q. Gadolinium has a low value of third ionisation enthalpy because of
A) high basic character
B) small size
C) high exchange enthalpy
D) hight electronegativity
Explanation
[Solution] Gd ($4f^75d^16s^2$) after losing 3 electrons gets the stable $4f^7$ configuration with high exchange enthalpy, so its third ionisation enthalpy is low. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.