NTA Abhyas JEE Main2020ChemistryClassification of Elements and Periodicity in PropertiesPractice
Which of the following represents the correct order of increasing first ionization enthalpy for Ca, Ba, S, Se and Ar ?
Options
- ABa < Ca < Se < S < Ar
- BCa < Ba < S < Se < Ar
- CCa < S < Ba < Se < Ar
- DS < Se < Ca < Ba < Ar
Correct answer
A. Ba < Ca < Se < S < Ar
Step-by-step solution
Ba < Ca < Se < S < Ar Ba, Ca belong to gr IIA ( alkaline earth metals) Se and S belong to gr Vl A (Chalcogens) and as we go down the group ionaization enthalpy decreases with increasing atomic size. So, Ba < Ca and Se < S Ar has stable completely filled electronic configuration and, therefore,has higest ionization enthalpy.Hence,the correct order is Ba < Ca < Se < S < Ar in kJmol − 1 503 590 941 999 1520