Earth's Atmospry: Heavier Elements, N2, O2, CO2, H2O

[pivoxa15]

The heavier elements tend to be found near Earth's surface than the lighter ones. However the most widely found element is N2 but elements like CO2 and O2 are other heavy ones so more near the Earth's surface? What about water? Is water mostly near Earth's surface or way above? If way above, is that why clouds are way above us and they are made out of water vapour?

Why is O2 clear and H2O which is lighter, white coloured in gas form? Is it because of the stronger intermolecular bonding between H2O?

 

[haiha]

CO2, N2 and O2 are not so different in weight so they mix well in the atmosphere. H2O vapor is even lighter than those gases. The clouds are made of water small droplets not only water vapour so the cloud's white colour is due to scattering effect, the Mie scattering.

 

[D H]

The Earth's atmosphere is a nearly uniform gaseous solution from sea level to about 100 km. Molecular scale forces and turbulent mixing dominate over gravity below this level. Above the 100km level, the long mean free path means gravity dominates over brownian motion and turbulence.