Why does hydrogen naturally form diatomic molecules (H2), whereas helium exists as a single atom (He)?

Hydrogen is a very reactive element. It doesn't exist as a single atom in nature. Neither do any of the other binary nonmetals -- nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. They're too prone to react with something. They react with each other and form binary molecules because the binary molecules are more stable than single atoms (by a lot!). Compounds with other atoms are even more stable, so hydrogen reacts with oxygen to form water, and chlorine reacts with sodium to form table salt.

Explanation:

~Hello~

imagine a space filled with some.big number of hydrogen atoms. As they bounce around, invariably they hit each other. When they do, they will only stick together if there is some energetic reason for doing so. The energetic reason is that when two hydrogen atoms stick together (bond), each proton is now interacting with two electrons, and each electron is interacting with two protons. So there is more overall attraction than in the previous individual case where each electron only interacted with one proton and vice versa.

Okay, so now you might ask "why don't three, or four, or more H atoms bond together, and create more attraction?". Well, because to interact with multiple protons, there is a very defined region of space that the electrons can occupy. For hydrogen atoms with a very small radius, that space is quite small, and can only hold two electrons before electron/electron repulsion becomes too strong.

Explanation:hope this helps brainlist pls