What is the Difference Between Electronegativity and Electron Affinity?

Electronegativity and electron affinity are related but distinct concepts in chemistry. The main difference between them lies in their definitions and applications:

Electronegativity:

• It is a chemical property that indicates an atom's ability to attract electrons towards itself.
• It is a qualitative property and is generally a unitless quantity, defined in regards to Pauling.
• Electronegativity values can change depending on the molecule it is in.
• It is relevant in bonded atoms, where the atom with higher electronegativity attracts electrons more in a bond.

Electron Affinity:

• It is a quantitative property, measured in units of kilojoules per mole (kJ/mol).
• It is the amount of energy released when an electron is added to a neutral atom.
• Electron affinity is a property of an isolated atom in the gaseous state.
• It is always a fixed and measurable value.

In summary, electronegativity deals with the attraction of electrons by individual atoms, while electron affinity deals with the energy released when an electron is added to an atom in a molecule. Both concepts are related to electron movement, but electronegativity is the result of the property of attraction, while electron affinity is the result of the change in energy.

Comparative Table: Electronegativity vs Electron Affinity

The difference between electronegativity and electron affinity can be summarized in the following table:

Electronegativity refers to an atom's ability to attract electrons in a chemical bond, while electron affinity refers to the amount of energy released when an electron is added to a neutral atom or molecule. Both properties are related to the movement of electrons, but they are not interchangeable. Electronegativity is determined by the attraction property, while electron affinity is determined by the change in energy.