Why is the H2 molecule more stable than two separate hydrogen atoms?

Answer 1

an H2 molecule has a completed valence electron shell, while an hydrogen atom still has one electron spot free in its outer (and only) orbital

Answer 2

A single H atom has a free electron, ie, valence 1. Anything with Valence 1 is most active, either give up the electron or grab another one to fill up the orbital (which requires 2 in this case). By sharing the 2 electrons, 2 H atom become more stable than single atom. That's not to say that H2 atoms don't react at all, they may find joining other compounds even better. That's why H2 alone is considered dangerous.

Answer 3

H2 is a molecule. Hydrogen is a diatomic molecule, which potential Hydrogen by employing itself exists as 2 Hydrogen atoms bonded to eachother. an simpler thank you to tell apart an atom and a molecule is that an atom is in simple terms that, a single atom. A molecule is constituted of extra effective than one atom, for this reason why H2 is a molecule and not an atom.

Answer 4

each hydrogen atom has 1 electron around a single proton.
when 2 H atoms come together the atomic orbitals overlap creating a molecular orbital. this allows the electrons more freedom, ie they are less confined, and hence lower energy. also, this molecular orbital is full (with 2e-) rather than only 1 as with the atomic orbital of an H atom. this means a H2 molecule is more stable than a unitary H atom.