Question

(A) : The second electron affinity of oxygen is endothermic.
(R) : Oxygen is the second highest electronegative element
The correct answer is:

• A. Both (A) and (R) are true and (R) is the correct explanation of (A)
• B. Both (A) and (R) are true and (R) is not the correct explanation of (A)
• C. (A) is true but (R) is false
• D. (A) is false but (R) is true

Answer 1

The correct option is B Both (A) and (R) are true and (R) is not the correct explanation of (A)

When we add second electron we need to supply energy to oxygen anion because of electron-electron repulsion. Hence endothermic. As oxygen gets octet if it accepts $2$ electrons and due to small size it is second more electronegative atom.