MCQ
Gadolinium has a low value of third ionisation enthalpy because of $......$
- ✓high exchange enthalpy
- Bhigh electronegativity
- Chigh basic character
- Dsmall size
✓
Answer
Correct option: A.
high exchange enthalpy
a
${ }_{64} Gd =[ Xe ] 6 s ^{2} 4 f ^{7} 5 d ^{1}$
${ }_{64} Gd =[ Xe ] 6 s ^{2} 4 f ^{7} 5 d ^{1}$
$Gd ^{+2}=[ Xe ] 4 f ^{7} 5 d ^{1}$
After losing $5 d$ electron $4 f$ has maximum exchange energy so Gd has low value of Third Ionisation energy
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