Question

An ionic compound $A^{+}{B}^{-}$ is most likely to be formed when :

• A. The ionization energy of $A$ is high and electron affinity of $B$ is low
• B. The ionization energy of $A$ is low and electron affinity of $B$ is high
• C. The ionization energy of $A$ and electron affinity of $B$ are high
• D. The ionization energy of $A$ and electron affinity of $B$ are low

Answer 1

The correct option is B The ionization energy of $A$ is low and electron affinity of $B$ is high

Ionization energy is defined as the energy required to remove an electron from a gaseous atom or ion. So, an atom with low ionization means that a small amount of energy is required by an atom to lose its loosely bound valence electron.

On the other hand, electron affinity is defined as the energy absorbed when an electron is added to an atom or molecule in the gaseous state. So, an atom with high electron affinity will readily accept an electron from another atom.

Hence, we can conclude that an ionic bond is most likely to be formed when the ionization energy of $A$ is low and the electron affinity of $B$ is high.

Thus, option (B) is correct.