The EA₂ of an oxygen atom is positive, even though its EA₁ is negative. Why does this change of sign occur? Which other elements exhibit a positive EA₂? Explain.

Electron affinity of 7th group elements whose electron affinity of their anionic forms ( EA2) are higher than the electron affinity of their neutral form(EA1). This is because their anionic forms are more stable than their neutral form. If the reaction is endothermic ,change in the energy is negative this means that electron affinity is positive. And vice versa for negative electron affinity.

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pstnonsonjoku pstnonsonjoku · Answer 2 · 2021-12-03T15:49:25+01:00

The EA2 of oxygen is positive because energy is required to add an electron to a small space that is already dense with negative charge. The EA2 of sulfur is also positive.

The electron affinity refers to the energy evolved when one mole of electrons is added to an atom. We know that the energy required to add the second electron to oxygen is positive rather than negative implying that the process is endothermic.

This is because, energy is required to add an electron to a small space that is already dense with negative charge. The EA2 of sulfur is also positive.

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