(solved)Question 3.21 of NCERT Class XI Chemistry Chapter 3

Would you expect the second electron gain enthalpy of O as positive, more negative or less negative than the first? Justify your answer.

Categories | About Hoven's Blog

Parveen,

Question 3.21
NCERT Class XI Chemistry

Would you expect the second electron gain enthalpy of O as positive, more negative or less negative than the first? Justify your answer.

Solution in Detail
(video solution below this)

Point 1: O atom is small in size.

Point 2: after addition of first additional electron the electron density in the already crowded valence shell becomes so high that a second additional electron experiences a significant amount of repulsion.

Point 3: The repulsion is so high that the process becomes endothermic.

Conclusion: the second electron gain enthalpy is positive and high! [found to be +844 kJ/mol]

Video Explanation

Please watch this youtube video for a quick explanation of the solution:

Creative Commons License
This Blog Post/Article "(solved)Question 3.21 of NCERT Class XI Chemistry Chapter 3" by Parveen is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.