Key Points:

1.What is electron affinity

2.Electron Affinity Examples

3. Electron Affinity Units

4.Is Electron Affinity endothermic or exothermic reaction

5. Electron Affinity Trends

Electron Affinity is defined as the minimum amount of energy released to gain the electron by isolated, neutral gaseous atom .This will result in the formation of negatively charged gaseous ion (anion).

For Example:

Formation of Chloride ion:

Electron Affinity Unit:

• eV (electron volts)
• KJ/mol

Is Electron Affinity endothermic or exothermic reaction ?

As the electron affinity is an energy output ( energy released ) to gain the negatively charged electron .Therefore , electron affinity is an exothermic reaction as it release energy .

Electron Affinity Trends across the Period:

It is generally observed that as we move from left to right in a periodic table, the electron affinity increases because the electrons are held tighter by the increase in the effective nuclear charge and the decrease in the atomic size.

Electron Affinity Trends down the Group:

It is generally observed that as we move from top to bottom in a periodic table, the electron affinity decreases because the electron shells increases ,results in the decrease of the effective nuclear charge and the increase in the atomic size.

Also Read!!

Ionization Energy Trends

Electronegativity trends

Which Factors Influence Electronegativity

Ionic Bond

Covalent Bond

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