Quick answerHydrogen (H) is a nonmetal with atomic number 1 and an atomic mass of 1.008 (2023), in group 1, period 1. It was discovered by Henry Cavendish in 1766. It is used for ammonia production for fertiliser and petroleum refining. Its electron configuration is 1s1.
The lightest element in the universe, hydrogen fuels the Sun and makes up about 75% of all normal matter. On Earth it is mostly locked up in water and organic molecules, and industry uses it to make ammonia fertiliser, refine oil, and, increasingly, as a clean fuel. Its single proton and single electron also make it the simplest atom there is.
Key facts
| Symbol | H |
|---|---|
| Atomic number | 1 |
| Atomic mass | 1.008 (IUPAC standard atomic weight, 2023) |
| Category | nonmetal |
| Group | 1 |
| Period | 1 |
| Block | s-block |
| Electron configuration | 1s1 |
| Discovered | Henry Cavendish, 1766 |
| Uses | ammonia production for fertiliser, petroleum refining, hydrogen fuel cells, rocket propellant, methanol production |
Overview
Hydrogen is the simplest and lightest of all the elements. Its atom holds a single proton and a single electron, and it sits in group 1, period 1 of the periodic table, with the electron configuration 1s1 and an atomic mass of 1.008. Hydrogen was first recognised as a distinct element by Henry Cavendish in 1766, although it had been produced unknowingly for centuries whenever acids met metals. It is by far the most abundant element in the universe, making up about 75% of all normal matter, and it is the fuel that powers the Sun: deep in the solar core, hydrogen nuclei fuse into helium and release the light and heat that reach Earth. On Earth, hydrogen rarely exists on its own. It is locked up in water, in natural gas and oil, and in every living thing, where it forms part of carbohydrates, proteins and DNA. Industry produces it in huge quantities, mostly from natural gas, and uses it to make ammonia for fertiliser, to refine petroleum, and to make methanol. It also fuels rockets and hydrogen fuel cells, which combine hydrogen with oxygen to make electricity and leave only water behind. Because it burns cleanly, hydrogen is increasingly seen as a fuel for a low-carbon future, although most of it is still made from fossil fuels today.
Frequently asked questions
What is hydrogen used for?
Hydrogen is mainly used to make ammonia for fertiliser and to refine petroleum, and it is also used to make methanol. It fuels rockets and hydrogen fuel cells, which generate electricity and leave only water behind. Because it burns cleanly, it is increasingly seen as a fuel for cars, heating and industry in a low-carbon future.
What is the symbol for hydrogen?
The chemical symbol for hydrogen is H, from its name, which comes from the Greek for water-former. It has atomic number 1, making it the first element in the periodic table, and its atom holds a single proton and a single electron. Its standard atomic mass is 1.008, the lightest of any element.
What is the atomic number of hydrogen?
Hydrogen has atomic number 1, so it is the first element in the periodic table. Its atom contains one proton and one electron, and its standard atomic mass is 1.008. It sits in group 1 and period 1, and its electron configuration is 1s1, the simplest of any element.
Is hydrogen a metal?
No, hydrogen is a nonmetal, even though it sits in group 1 with the alkali metals. It is a colourless, odourless gas at room temperature and does not behave like a metal under normal conditions. Under extreme pressure, such as inside giant planets, it can take on metallic properties, but that is not its everyday form.
Where is hydrogen found?
Hydrogen is the most abundant element in the universe, making up about 75% of all normal matter and fuelling the stars. On Earth it is almost never found as a free gas, but locked up in water, in natural gas and oil, and in every living thing. Industry produces it mostly from natural gas.
Quick quiz
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Keep exploring
- Periodic table — all 118 elements
- Carbon (C) — another nonmetal, atomic number 6
- Nitrogen (N) — another nonmetal, atomic number 7
- Oxygen (O) — another nonmetal, atomic number 8
- Phosphorus (P) — another nonmetal, atomic number 15
- Sulfur (S) — another nonmetal, atomic number 16
- Selenium (Se) — another nonmetal, atomic number 34
Sources & last updated
- CIAAW — Standard Atomic Weights
- PubChem Periodic Table
- Wikipedia — Timeline of chemical element discoveries
Last updated: . Figures are shown with their year; where sources disagree, the value is left out rather than estimated.