JEE MainChemistryClassification of Elements and Periodicity in Properties
Identify the incorrect statement among the following.
Options
- AThe third ionization enthalpy of Al is significantly greater than the third ionization enthalpy of Mg .
- BThe second ionization enthalpy of Cu is higher than the second ionization enthalpy of Zn .
- CThe second ionization enthalpy of Cr is higher than the second ionization enthalpy of Mn .
- DThe first ionization enthalpy of Zn is higher than the first ionization enthalpy of Ga .
Correct answer
A. The third ionization enthalpy of Al is significantly greater than the third ionization enthalpy of Mg .
Step-by-step solution
Let us evaluate each statement by writing the electronic configurations of the relevant atoms and ions. For Mg ( Z=12 ): The configuration is [ Ne ] 3s^2 . After removing two electrons, Mg ²⁺ attains the stable noble gas configuration of Neon ( 1s^2 2s^2 2p^6 ). Removing a third electron requires breaking this highly stable core, so the third ionization enthalpy ( IE₃ ) of Mg is extremely high. For Al ( Z=13 ): The configuration is [ Ne ] 3s^2 3p^1 . After removing two electrons, Al ²⁺ has the configuration [ Ne ]