In our known universe, hydrogen then helium. But this may change with further exploration.
diffusion is dependent on chemical reactivity (can't diffuse if you're in a bond) and mass. So the lightest most un-reactive gases will diffuse the quickest. Helium would seem to be the best contender. diffusion is dependent on chemical reactivity (can't diffuse if you're in a bond) and mass. So the lightest most un-reactive gases will diffuse the quickest. Helium would seem to be the best contender.
There are more than two gases in the atmosphere. You need to specify the ones you are asking about.
The second lightest element on the periodic table is Helium (He). The easiest way to tell this is by the numbers on the periodic table, all elements are in atomic weight order (super-light gases to super-heavy elements).
Greenhouse gases surround the Earth. Greenhouse gases surround the Earth. Greenhouse gases surround the Earth.
hydrogen
It is highly flammable, it is the lightest of all gases and it is the most abundant element in the universe.
the lightest elements are gases and the lightest of these are hydrogen and helium.
Hydrogen. It is the lightest element in the known universe.
No, it is a colorless, highly flammable gaseous element, the lightest of all gases and the most abundant element in the universe.
Hydrogen and helium are the two main gases in the Universe.
The lightest and most abundant element in the entire Universe is hydrogen. Hydrogen has an atomic mass of nearly one.
Because in our universe they are the simplest.
Yes it is, and it's also the lightest gas in the universe.
Lithium!
hydrogen
the noble gases would be the lightest, as they are all gases
The lightest 'non-metal' could be Hydrogen and Helium! Both are gases, and therefore, not a metal.