99 Percentile Qs Bank for JEE MainChemistryClassification of Elements and Periodicity in Properties
Within each pair of elements F and C l , S and S e , and Li   and Na , respectively, the elements that release more energy upon an electron gain are
Options
- AC l , S e and N a
- BC l , S and L i
- CF , S and L i
- DF , S e and N a
Correct answer
B. C l , S and L i
Step-by-step solution
(i) Electron affinity of second period p -block element is less than third period p -block element due to small size of second period p -block element, due to small size electron density is more and upcoming electron face extra repulsion, so energy release is less. Hence, EA order: F < Cl . (ii) Down the group electron affinity decreases due to size increases. EA order: S > Se   Li > Na .