H2 is the chemical formula for dihydrogen, also known as diatomic hydrogen, hydrogen gas and molecular hydrogen. This is the naturally existing form of elemental hydrogen.
Hydrogen is the most abundant element in the known universe. It is also the simplest element, with only one proton and one electron. The most common isotope of hydrogen has only one proton in the nucleus. The second most common isotope has one neutron and is called deuterium. Tritium is the least common isotope because it is unstable and radioactive. It has two neutrons in the nucleus.
Properties of diatomic hydrogen include:
- Reacts with diatomic oxygen to form water
- Generated by the reaction of aluminum and a strong acid
- Reduces metal oxides
- Lighter than air
Hydrogen is used to:
- Fix nitrogen gas into ammonia for plants
- Produce saturated fats for the food industry
- Produce metals from their ores
- Fuel rockets