MHT CET20249 May 2024Evening ShiftChemistryClassification of Elements and Periodicity in PropertiesActual
Which from following elements has highest value of ionization enthalpy ( ₁ H ₁ ) ?
Options
- AHe
- BAr
- CCl
- DI
Correct answer
A. He
Step-by-step solution
The ionization enthalpy (I.E.) is highest for the inert gases. Therefore I.E of Ar and He will be higher than the halogens Cl and I . Down the group, I.E decreases due to increase in the atomic size. Therefore, ionization enthalpy of He Ar . varies as: I Cl and Ar He . Across a period, I.E increases with increase in atomic number. Therefore, I.E of Cl and Ar is in the order: Cl Ar . Hence, the correct increasing order of ionization enthalpy for the given elements is: I Cl Ar He He has the highest I.E.