* Nitrogen (N2): It makes up about 78% of the air we breathe. Nitrogen is very unreactive because the strong triple bond between the nitrogen atoms makes it difficult to break apart and participate in chemical reactions.

* Argon (Ar): It makes up about 1% of the air. Argon is a noble gas, which means it has a full outer shell of electrons and therefore doesn't readily form chemical bonds.

While there are trace amounts of other unreactive gases in the air, these two are the most significant.