The term 'Hydrogen Has One' refers to the fact that hydrogen atoms have one ELECTRON and one proton. Hydrogen is the simplest and most abundant element in the universe, making up about 75% of all matter. It is also the lightest element, with an atomic weight of 1.008. The ELECTRON and proton are the two subatomic particles that make up a hydrogen atom. The ELECTRON has a negative charge and is found in the outermost shell of the atom, while the proton has a positive charge and is found in the nucleus.