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Why is the first electron affinity exothermic?

Answer 1

Sometimes it is; especially for elements to the right of the Periodic Table.

The reaction's enthalpy is known as the electron affinity:

#M(g) + e^(-) rarr M^(-)(g)#

Because of the increased nuclear charge, we would anticipate that this enthalpy would increase across a Period from left to right and decrease down a Group as the nuclear charge is insulated by intervening electron shells.

Because they are reducing species, metals typically have low electron affinities.

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Answer 2

Owen Ambrose

The first electron affinity is exothermic because energy is released when an electron is added to a neutral atom to form a negatively charged ion. This is because the incoming electron is attracted to the positively charged nucleus of the atom, resulting in a release of energy as the electron occupies a lower energy level closer to the nucleus.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.