Question

explain why a hydrogen atom can become either an ion or a part of a molecule.

Answer 1

It can be an Ion because it is small with a low electronegativity (it gets bullied and loses its lone electron). An ion is defined as a particle that's lost or gained an electron, in this case Hydrogen will be losing an electron making it H+

It also really wants to be part of a molecule because it has a single valence electron, but it wants 2 to fill up it's shell! To do this it can combine with, as an example, Oxygen making H2O.

Hope that helps!