Question

Why are noble gases chemically inert?

Answer 1

Hint: The 18 group elements of the periodic table are known as Noble gases because they are chemically inert in nature. They do not react with any element as well. These gases are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).

Complete step by step answer:
The term chemically inert emphasise that the substance or the element is not chemically reactive and is thermodynamically unstable in nature as well that is the thermodynamic feasibility of the reaction is difficult to determine but such gases do decompose slowly.
The main reason for the inertness of the Noble gases is because of the completely filled last shell with the 8 electrons which completes its octet and further the electron cannot be given or taken from them since a large amount of energy is required to remove the electron which is thermodynamically not feasible.
The $2n^2$ rule is commonly followed for the filling of the electrons in the shell. Where n is the number of shell K, L, M and N respectively. Further Pauli’s Exclusion principle and Aufbau rule are also followed for the filling of electrons in the orbitals.
Only Xenon and Fluorine are known to form the bonds with each other, but a large amount of energy is required to derive such reactions along with the use of the catalyst and the other physical parameters and thus only helium and Neon are regarded as completely inert gases. Such compounds if prepared are kept in moisture proof conditions in order to prevent their decomposition.

Note:
Due to the inert nature of these gases they are widely used in the storage containers for the oxygen sensitive substances, in fluorescent lamps and in the air balloons in order to prevent the other reactions which can alter the results and thus with the help of these gases desired products are obtained.