* Nitrogen (N2): Makes up approximately 78% of the atmosphere.

* Oxygen (O2): Makes up approximately 21% of the atmosphere.

These two gases together make up over 99% of the Earth's atmosphere.

Here are some other important components of the atmosphere:

* Argon (Ar): Makes up about 0.93% of the atmosphere.

* Carbon dioxide (CO2): While a small percentage, it plays a crucial role in the Earth's climate.

* Water vapor (H2O): The amount of water vapor varies greatly depending on location and weather conditions.

* Other gases: There are trace amounts of other gases like neon, helium, methane, and ozone.

It's important to note that the composition of the atmosphere can vary slightly depending on factors like altitude, location, and time of day.