Which gas is the most abundant in the Earth's atmosphere?

Nitrogen is the most abundant gas in the Earth's atmosphere, making up about 78% of the total atmospheric composition. Its dominance is crucial because it plays a significant role in the chemical processes that occur in the atmosphere, including the nitrogen cycle, which is vital for life on Earth. Nitrogen is relatively inert, meaning it does not readily react with other substances, allowing it to remain stable in the atmosphere over long periods.

Oxygen, while essential for life and present in roughly 21% of the atmosphere, does not match nitrogen in abundance. Carbon dioxide and hydrogen exist in much smaller quantities, with carbon dioxide constituting about 0.04% of the atmosphere, and hydrogen forming only trace amounts. Understanding the composition of the atmosphere is important for grasping how it supports life and influences weather patterns.