Question

The noble gases are unreactive because:
A) Have same number of electrons
B) Have atomicity of one
C) Are gases with low density
D) Have stable electronic configuration

Answer 1

Hint: We have to know that the noble gas belongs to group $18$ in the periodic table, they have stable electronic configuration as the octet for each element present in noble gas is complete which makes the electronic configuration stable. Sometimes, noble gases are also known as inert gas.

Complete answer:
We will look at all the options for answering this question:
Option A) this option can be right as the number of valence electrons for noble gas is the same which is eight and that completes the octet for noble gases thus forming a stable electronic configuration.
Option B) this option can be correct as atomicity of noble gases is $1$ which is monoatomic as atomicity defines the number of atoms present in a molecule. Thus noble gases are monatomic since they have only one atom in a molecule, for example: Helium gas containing only one helium atom.
Option C) this option can be correct as noble gas has low density but density increases going down the group thus all noble gases have different densities and not the same.
Option D) this is a correct option as there are many reasons for making a noble gas unreactive but in it the most common and most important that makes a noble gas unreactive is its electronic configuration.

Note:
We have to know that all the options given above are correct for the reactivity of noble gases but on priority it’s the electronic configuration that works. Since having a complete octet makes noble gases having a stable electronic configuration.