Hydrogen (atomic symbol H) is the first element on the periodic table and the lightest of all the elements. It is composed of a single electron and a single proton. By weight it makes up 90 percent of the universe. This is because it is involved in the chemical make-up of all organic compounds, and water (H2O) is essential to life. Hydrogen received its name in 1983 from French scientist Antoine Lavoisier. He derived the name from the Greek words “hydro” meaning “water” and “genes” meaning “generator” because other experiments revealed that it produced water. It is believed to be one of the three elements created in the Big Bang, along with helium and lithium.
In the early 16th century, hydrogen was observed and recorded for the first time by Theophrastus Paracelsus. The physician dissolved iron in sulphuric acid and realized that it produced a gas. He learned nothing else about the gas. In 1670, Robert Boyle repeated Paracelsus’ experiment, and he realized that the gas only burned in the presence of air and that part of the air would be consumed. Later, Boyle’s “air” would be identified as oxygen. Then in 1766, hydrogen was officially identified as an element by the English chemist and physicist Henry Cavendish. Cavendish created a reaction between hydrochloric acid and zinc, which released hydrogen. He performed another number of experiments with different metals and different acids, all of which released this same gas. He finally collected it over mercury, but incorrectly concluded that it was expelled by the metals when it was really being released by the acids.
Over the next few decades, more experiments with hydrogen were completed. John Dalton created his theory of atoms by studying hydrogen. Electrolysis was used by Sir William Robert Grove to divide water into hydrogen and oxygen. After twenty-seven years of work, Dr. Francis Thomas Bacon powered a welding machine with nickel gauze and sulphuric acid, which contains hydrogen. Based upon his design, NASA created the fuel cells used for the Apollo space missions. Combining hydrogen with liquid oxygen makes rocket fuel. Commercially, hydrogen is very important. It is combined with nitrogen to form ammonia (NH3), used in fertilizer and cleaning products. It is added to peanut and other oils to create hydrogenated oil, which prolongs the shelf life of foods.
A failed use of hydrogen occurred in the 1937 Hindenburg disaster, in which hydrogen was used as a lifting agent instead of helium in the huge zeppelin. Hydrogen, lighter than helium, was used as a money-saving maneuver. A hydrogen-filled airship can be smaller than a helium-filled one while carrying the same payload. The craft burst into flames in Lakehurst, New Jersey, and was not the first hydrogen airship to do so, but was the largest. This was due to the highly flammable nature of the element.
In addition to being flammable, flames produced by hydrogen are nearly invisible. It has violent reactions with oxidants, as well as chlorine and fluorine. In its most common form, it is a colorless and odorless gas, existing as diatomic molecules of H2. On earth, there is very little free hydrogen because it is too light to be held by gravity. It is classified as a non-metal, but it becomes a liquid metal under enormous pressure, like that of the magnetic field of the planet Jupiter. The sun burns hydrogen in a process called fusion to produce energy, as do most other stars.
Along with water and ammonia, hydrogen forms numerous other compounds such as methane (CH4), sugar (C12H22O11), peroxide (H2O2) and hydrochloric acid (HCl). It has three common isotopes: protium (normal hydrogen), deuterium, and tritium. Deuterium is stable, while tritium is not. The latter is, in fact, radioactive. Hydrogen is an important element commercially and scientifically, but also in life itself and the formation and functioning of our solar system. For the simplest element, it has a long and interesting history.
