Concept:The Earth’s atmosphere is mostly made of nitrogen and oxygen. Nitrogen is the most abundant gas by volume.Explanation:Air contains a mixture of gases. The main gases and their approximate percentages by volume are listed below.Nitrogen = about 78%Oxygen = about 21%Argon = about 0.9%Carbon dioxide = about 0.04%Other gases are present in very small amounts.The exact composition is given in the table.
Permanent Gases of the Atmosphere
Constituent
Per cent by Volume
Nitrogen (N2)
78.084
Oxygen (O2)
20.946
Argon (Ar)
0.934
Carbon dioxide (CO2)
0.036
Neon (Ne)
0.00182
Helium (He)
0.000524
Krypton (Kr)
0.000114
Hydrogen (H2)
0.00005
From the table, nitrogen is 78.084% of air by volume. For most purposes, this is rounded to 78%.
