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?