Question
The formation of the oxide ion O2-(g) requires first an exothermic and then an endothermic step as shown below
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Oxygen is more electronegative
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O- ion has comparatively larger size than oxygen atom
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O- ion will tend to resist the addition of another electron
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Oxygen has high electron affinity
Solution
C.
O- ion will tend to resist the addition of another electron
This process is unfavourable in the gas phase because the resulting increase in electron-electron repulsion overweights the stability gained by achieving the noble gas configuration.
