Question

Assertion (A): Noble gases have highest ionization energies in their respective periods.
Reason (R): The outermost shell of noble gases is completely filled.

• A. Both $A$ and $R$ are correct and $R$ is the correct explanation of $A$.
• B. Both $A$ and $R$ are correct and $R$ is not the correct explanation of $A$.
• C. $A$ is true but $R$ is false.
• D. $A$ is false but $R$ is true.

Answer 1

The correct option is B Both $A$ and $R$ are correct and $R$ is not the correct explanation of $A$.

In any given period, the noble gas element has highest ionization enthalpy. The valence shell of noble gases is completely filled. This closed shell electronic configuration is very stable. Large amount of energy is required to remove an electron from a completely filled outermost shell.