By mass:
* No. Hydrogen is actually the most abundant element in the universe by mass, but in the Earth's atmosphere, it's only present in trace amounts. Nitrogen is the most abundant gas in the Earth's atmosphere, followed by oxygen.
By number of atoms:
* Yes. Even though hydrogen is light, it's actually the second most abundant element in the Earth's atmosphere by number of atoms. This is because there are many more individual hydrogen atoms compared to heavier atoms like nitrogen and oxygen.
So, the answer is:
* By mass, no.
* By number of atoms, yes.
