* Nitrogen (N2): Makes up about 78% of the atmosphere. It's relatively inert, meaning it doesn't easily react with other substances.

* Oxygen (O2): Makes up about 21% of the atmosphere. Essential for life, as it's used by plants and animals for respiration.

* Argon (Ar): Makes up about 0.93% of the atmosphere. It's also inert and is used in various industrial applications.

Other gases present in much smaller amounts:

* Carbon dioxide (CO2): While a small percentage, it plays a significant role in the Earth's climate. It's a greenhouse gas, trapping heat and contributing to global warming.

* Neon (Ne), Helium (He), Methane (CH4), Krypton (Kr), Hydrogen (H2), and Xenon (Xe): These gases exist in trace amounts.

Water Vapor (H2O): While not a permanent component of the atmosphere, water vapor varies greatly depending on location and weather conditions. It plays a crucial role in weather patterns and the Earth's climate.

Aerosols: These are tiny particles suspended in the air, including dust, pollen, smoke, sea salt, and volcanic ash. They can affect sunlight, cloud formation, and air quality.

It's important to remember that the composition of the atmosphere varies slightly depending on altitude. The higher you go, the thinner the air becomes and the gases become less concentrated.