Published by:
CGP EDU Academic Team
Published on: August 13, 2026
The first ionisation enthalpies of 
and Si are in the order:
A
B
C
D
Text Solution
Verified by ExpertsThe correct answer is:
A
The electronic configurations are as follows:
Ionization enthalpy increases as we move across the period. The I.E. of Mg will be greater than that of Na due to fully filled electronic configuration. The I.E. of Al will be smaller than that of Mg due to 
extra than the stable electronic configuration. Hence, the correct order is 
.
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