What is Hydrogen?
Hydrogen is the first element of the periodic table. It is the simplest possible atom consisting of a proton in a nucleus orbited by an electron. Hydrogen is the lightest and most abundant element in the universe.
Characteristics and Properties
At normal temperature and pressure, hydrogen is a colorless, odorless and tasteless gas.
Hydrogen is very flammable and burns with an invisible flame. It burns on contact with oxygen. The byproduct of the hydrogen and oxygen explosion is water or H2O.
Hydrogen gas is made up of diatomic molecules called H2.
Highlights of Hydrogen:
| Symbol | H |
| Atomic Number | 1 |
| Atomic Weight | 1.00794 |
| Classification | Nonmetal |
| Phase at Room Temperature | Gas |
| Density | 0.08988 g/L @ 0°C |
| Melting Point | 259.14°C, -434.45°F |
| Boiling Point | 252.87°C, -423.17°F |
| Discovered by | Henry Cavendish in 1766 |
Where is Hydrogen found on earth?
The most common place to find hydrogen on earth is in water. Each water molecule (H2O) contains two hydrogen atoms. Hydrogen is also found in a wide range of compounds throughout the earth, including hydrocarbons, acids, and hydroxides.
There is very little free hydrogen in the Earth’s atmosphere because it is so light that it eventually escapes into space. The only free hydrogen on earth is found deep underground.
Stars and Planets
Hydrogen is mainly found in stars and gas giant planets. The sun consists mainly of hydrogen. Deep inside stars, the pressure is so high that hydrogen atoms are converted to helium atoms. This conversion is called fusion and releases the heat and energy that we think of as sunlight.
How is Hydrogen used today?
Hydrogen is a very useful element. It is used to produce ammonia for fertilizers, refine metals, and methanol to produce man-made materials such as plastics.
Hydrogen is also used as a rocket fuel where liquid hydrogen is combined with liquid oxygen to create a powerful explosion. Scientists hope that hydrogen could one day be used as a clean alternative to gasoline.
How was Hydrogen discovered?
British scientist Henry Cavendish discovered hydrogen as an element in 1766. Cavendish conducted an experiment using zinc and hydrochloric acid. He discovered hydrogen and also discovered that it produces water when burned.
Where did Hydrogen get its name?
The name hydrogen is derived from the Greek words “hydro” (meaning water) and “gen” (meaning creator). It was named by French chemist Antoine Lavoisier because when burned it “creates water”.
Ions and Isotopes
Hydrogen can carry a negative charge and is an anion called a hydride. It can also carry a positive charge as a cation.
Protium is the most common isotope of hydrogen. It has no neutrons and only one proton. Other common isotopes include deuterium and tritium.
Interesting Facts about Hydrogen
Scientists estimate that hydrogen makes up more than 90% of all atoms in the universe.
It is the only element that can exist without neutrons.
Hydrogen becomes a liquid at very low temperatures and high pressures. Under extreme pressure, it can become liquid metal. Metallic hydrogen is thought to exist at the core of gas giant planets like Jupiter.
About 10% of the human body mass is made up of hydrogen.
Because it is so light, it was once used in lighter-than-air balloons. However, it has become too dangerous due to its highly flammable nature.
Hydrogen gas can be made in the laboratory by combining dilute acids with metals.