The Periodic Table

Hydrogen

Name: Hydrogen

Symbol: H

Atomic Mass: 1.00794 u ± 0.00001 u  

Atomic Number: 1

Boling Point:  -252.9 °C

Melting Point: -259.2 °C 

 Electron configuration: 1s1

Discoverer: Henry Cavendish

The most abundant element in the universe, hydrogen is also a promising source of "clean" fuel on Earth.

Named after the Greek words hydro for "water" and genes for "forming," hydrogen makes up more than 90 percent of all of the atoms, which equals three-quarters of the mass of the universe, according to the Los Alamos National Laboratory. Hydrogen is essential for life, and it is present in nearly all the molecules in living things, according to the Royal Society of Chemistry. The element also occurs in the stars and powers the universe through the proton-proton reaction and carbon-nitrogen cycle. Stellar hydrogen fusion processes release huge amounts of energy as they combine hydrogen atoms to form helium, according to Los Alamos.

Pure hydrogen gas is scarce in Earth's atmosphere and any hydrogen that actually enters the atmosphere rapidly escapes Earth's gravity, according to the Royal Society. On our planet, hydrogen occurs mainly in combination with oxygen and water, as well as in organic matter such as living plants, petroleum, and coal.