Question

Why do noble gases have positive electron gain enthalpy?

• A. It is difficult to add an electron due to small size.
• B. It is difficult to add an electron due to high electronegativity.
• C. It is difficult to add an electron due to stable configuration.
• D. It is difficult to add an electron due to high electron affinity.

Answer 1

Answer: (C)

It is difficult to add an electron due to stable configuration.

Due to the stable configuration, they do not accept an electron and hence they have large positive electron gain enthalpy.

An electron has to enter the next higher principal quantum level which leads to a very unstable electronic configuration.

Hence, the correct option is $\text{C}$