Question

The compound $X^{+}{Y}^{-}$ is formed when:

• A. Electron affinity of Y is low and ionisation energy of X is high
• B. Electron affinity of Y is high and ionisation energy of X is low
• C. Both electron affinity of Y and ionisation energy of X is high
• D. Both electron affinity of Y and ionisation energy of X is low

Answer 1

The correct option is B Electron affinity of Y is high and ionisation energy of X is low

Ionic compounds are formed between elements out of which one of the species is electropostive and the other is electronegative. The above compound can be formed only when X can easily lose electron and Y can accept electron easily i.e ionisation energy of X should be low and electron affinity of Y should be high .