Question

The noble gases are unreactive because

• A. they have a large number of protons.
• B. their valence shell is completely filled with electrons.
• C. their valence shell is half filled with electrons.
• D. they have a large number of neutrons.

Answer 1

The correct option is B their valence shell is completely filled with electrons.

Noble gases have stable configuration due to the presence of 8 electrons in their valence shell ie., they are unreactive. Other elements react by gaining or losing electrons to attain stable configuration of the nearest noble gas. Helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn) are the elements of group 18. The members of the group have eight electrons in their outermost orbit (except helium which has two electrons). Thus, they have a stable configuration.