Question

carbon dioxide is generally heavier than oxygen and nitrogen . why does it not form lower layer in the atmosphere?

Answer 1

carbon dioxide is heavier than air, but it has a tendency to mix with other gases of air and since the rest gases are found at higher altitude so the carbon dioxide could not be able to be in the lower layer of atmospheric air.

Answer 2

although carbon dioxide is heavier than nitrogen and oxygen it has tendency to mix up with other gases which are found at higher altitude. This is the reason why carbon dioxide not form the lower layer in the atmosphere.