Question

Noble gas are chemically inactive because of :

• A. monoatomic nature
• B. low boiling points
• C. completely filled valence shell
• D. rare occurence

Answer 1

The correct option is C completely filled valence shell

In general, noble gases are least reactive. Their inertness to chemical
reactivity is attributed to the following reasons:
(i) The noble gases except helium $1s^2$ have completely filled $n{s}^{2}n{p}^6$ electronic configuration in their valence shell.
(ii) They have high ionisation enthalpy and more positive electron gain enthalpy.
Noble gases have no tendency to gain lose or share electrons, They do not participate in chemical reactions, because their outermost electron shell (valence shell) is completely filled, so that they have little tendency to gain or lose electrons.

An atom with a closed shell of valence electrons tends to be chemically inert. Thus option (c) is the correct answer.