Why does hydrogen gas not exist in Earth's atmosphere?

There are many factors responsible for that some of those are : Hydrogen is the lightest element yet found thus when produced in free form it rises above all the other gases to the top of the atmosphere where it is open to cosmic storms and solar flares. There it literally leaks from the atmosphere to the empty space. read more

Hydrogen is the lightest element yet found thus when produced in free form it rises above all the other gases to the top of the atmosphere where it is open to cosmic storms and solar flares. There it literally leaks from the atmosphere to the empty space. read more

This is an intuitive, approximate explanation of why the molecular hydrogen concentration in Earth's atmosphere is really low, while the concentration of other, heavier molecules is higher. There is a difference in the probability, for a certain molecule, to have a speed greater or equal to the escape speed of the Earth. read more

The helium atom does not form a diatomic molecule, unlike the main components of the atmosphere, nitrogen and oxygen, and it is a very light atom, actually the second lightest of all atoms (second only to hydrogen) and it is gravity which holds our atmosphere in place on the surface of the Earth, so the lighter the particle, the more easily it can escape into space. read more