Question

Why Noble gases inert in nature?

Answer 1

Look at the atomic no. and valencies of these gases and also Inert means "chemically inactive". These gases belong to the Group 18 in the periodic table.

Complete answer:
The noble gases are a family of elements, and all of them are located in the far right column of the periodic table. Their group is 18. Noble Gases includes Helium, Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn).
Meaning of inert is not reactive or it means that they are chemically stable. In case of Noble gases they have full octets that means that they do not have free electrons to react or to make chemical bonds. So they have more stability than any other group’s elements. Because of more stability, then don't react with anything. So they are inert in nature.
It is inert or not reactive because it does not involve chemical bonding - gaining or losing of electrons with other elements at normal temperature and pressure. It has an octet or duplet valence shell structure, a stable electronic configuration hence it won't participate or very unlikely to participate in a reaction to gain or lose electrons causing it to be known as inert. Every element reacts to attain stability but all the noble gases are already stable.

Note: Unstable Kr compounds and stable Xe compounds are also formed but at a very high temperature and pressure.
Whenever it is asked to tell about chemical reactivity then first have a look at the electronic configuration. The general electronic configuration of noble gases is $ns^2, np^6$.