Hydrogen is nonmetallic (except when it becomes metallic at extremely high pressures) and readily forms a single covalent bond with most nonmetallic elements, forming compounds such as water and nearly all organic compounds.
Deuterium is a stable isotope of hydrogen, which, unlike “normal” hydrogen atoms, or protium, also contains a neutron. The isotope deuterium has one proton, one neutron and one electron. One out of 6420 hydrogen atoms, on average, is a deuterium isotope.