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What does electron affinity determine?

Answer 1

Electron affinity EA measures the energy released when an electron adds to a gaseous atom. For example,

Cl(g) + e⁻ → Cl⁻(g); EA = -349 kJ/mol

The negative sign shows that the process releases energy.

Adding an electron to a metal requires energy. Metals are much more likely to give up their electrons. Thus, metals have positive electron affinities. For example,

Na(g) + e⁻ → Na⁻(g); EA = 53 kJ/mol

In the Periodic Table, electron affinity increases (becomes more negative) from left to right in a period. Electron affinity decreases from top to bottom in a Group. But there are some exceptions.

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Answer 2

Caleb Adams

Electron affinity determines the energy change that occurs when an electron is added to a neutral atom to form a negative ion.

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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.