Hydrogen is the lightest, smallest, and simplest element. It consists of one proton and one electron.
Because it is so light, you can fill a balloon with it that will immediately rise. In 1766, scientist Henry Cavendish succeeded in identifying hydrogen. As a gas (H2), hydrogen is colourless, odourless, non-corrosive, non-oxidizing, non-radioactive and non-toxic.
Hydrogen in a usable form for energy does not occur in nature and must be made, by splitting off the hydrogen atoms from other molecules; for example, from natural gas (CH4) or from water (H2O). This requires energy. The result is the energy-rich molecule hydrogen. When heat is applied – a flame – hydrogen reacts with oxygen to form water again. This releases a considerable amount of energy: 125 MJ per kilogram of hydrogen: 3.5 times as much as a liter of gasoline. Because of the fierce reaction when ignited, hydrogen was also known as ‘bang gas.’