Which element is most abundant in Earth's atmosphere?

Which element is most abundant in Earth's atmosphere?

• A. Oxygen
• B. Argon
• C. Nitrogen
• D. Carbon dioxide

Answer: (C)

Nitrogen dominates Earth's atmosphere. It exists as diatomic molecules (N2) and makes up about 78% of dry air, which is far more than any other gas. The next major component is oxygen, at roughly 21%, while argon, carbon dioxide, and other trace gases together add up to less than 1%. Nitrogen’s high abundance comes from its relative chemical inertness in atmospheric conditions, so it stays in the air instead of reacting away, whereas the smaller amounts of argon and carbon dioxide are by comparison, present only in trace quantities. Oxygen is plentiful and essential for life and many processes, but it is not the most abundant gas in the atmosphere.

Nitrogen dominates Earth's atmosphere. It exists as diatomic molecules (N2) and makes up about 78% of dry air, which is far more than any other gas. The next major component is oxygen, at roughly 21%, while argon, carbon dioxide, and other trace gases together add up to less than 1%. Nitrogen’s high abundance comes from its relative chemical inertness in atmospheric conditions, so it stays in the air instead of reacting away, whereas the smaller amounts of argon and carbon dioxide are by comparison, present only in trace quantities. Oxygen is plentiful and essential for life and many processes, but it is not the most abundant gas in the atmosphere.