Class 12 NEET Chemistry D And F Block Elements Questions

Electronic configuration of Gadolinium
Gd :- [Xe] 4f75d16s2
In case of 3‌rd ‌ ionisation enthalpy electron will be removed from 5d and resultant configuration will be [Xe]4f f⊤ that is stable electronic configuration as it will have high exchange energy, hence less energy will be required to remove 3‌rd ‌ electron.