Hi, quite new in chemistry.. I would like to know the beginning of the atoms in the universe. Therefore I must understand the process from Hydrogen to Helium. But to create Helium you need the isotope(#2) "Deuterium" from Hydrogen. But how did the Deuterium form? From two Protons colliding or did two Protium (also an isotope, #1)-atoms became a pair? If it became a pair, how could they resist the repelling force between them?