First electron affinity for oxygen is exothermic but second electron affinity for oxygen is endothermic.explain

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Solution

$E l e c t r o n a f f i n i t y i s t h e e n e r g y c h a n g e i n a n a t o m w h e n a n e l e c t r o n i s a d d e d t o a n e u t r a l g a s e o u s a t o m . I n o x y g e n O + e^{-} \to O^{-} F i r s t E A = - 142 k J / m o l T h e f i r s t e l e c t r o n a f f i n i t y i s n e g a t i v e s h o w i n g i t s e x o t h e r m i c, e n e r g y i s r e l e a s e d d u r i n g t h e a d d i t i o n o f e l e c t r o n t o t h e n e u t r a l a t o m . O^{-} + e^{-} \to O^{2 -} S e c o n d E A = + 844 k J / m o l T h e s e c o n d r e a c t i o n i s e n d o t h e r m i c s h o w i n g t h a t e n e r g y i s a b s o r b e d t o p e r f o r m t h i s c h a n g e . T h e s e c o n d e l e c t r o n a f f i n i t y o f o x y g e n i s h i g h b e c a u s e t h e e l e c t r o n i s a d d e d f o r c e f u l l y t o a s m a l l, v e r y d e n s e s p a c e . A s w e l l a s i t s a d d e d t o a n a l r e a d y n e g a t i v e i o n .$

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Similar questions

Q. Which has greater second electron affinity : sulphur or oxygen? why?

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

Q. The electron affinity of sulphur is -200 kJ/mol. Then the electron affinity of oxygen is :

Regarding assertion and reason, choose the correct option.

Assertion [A]: The affinity of hemoglobin for oxygen is dependent on the partial pressure of oxygen.

Reason [R]: Hemoglobin has a low affinity for oxygen.

Q. For a neutral atom, the first ionization energy is equal to its electron affinity.

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