If there is one half-remembered chemical fact that most of us carry from our schooldays, it is that the inert or “noble” gases do not react. The noble gases have full outer shells of electrons, and so cannot share other atoms' electrons to form bonds. ...

Do noble gases never react?

Noble gases are the least reactive of all elements. That's because they have eight valence electrons, which fill their outer energy level. This is the most stable arrangement of electrons, so noble gases rarely react with other elements and form compounds.

Do noble gases react naturally?

At the top of the noble gases is little helium (He), with a shell that is full with only two electrons. The fact that their outer shells are full means they are quite happy and don't need to react with other elements. In fact, they rarely combine with other elements. That non-reactivity is why they are called inert.