Symbol

H

Atomic Number

1

Atomic Mass

1.00794

Family

Group 1 (Ia) Pronunciation

HY-dru-jin

Overview

Hydrogen is the most abundant element in the universe. Nearly nine out of every ten atoms in the universe are hydrogen atoms. Hydrogen is also common on the Earth. It is the third most abundant element after oxygen and silicon. About 15 percent of all the atoms found on the Earth are hydrogen atoms.

Hydrogen is also the simplest of all elements. Its atoms consist (usually) of one proton and one electron.

Hydrogen was first discovered in 1766 by English chemist and physicist Henry Cavendish (1731-1810). Cavendish was also the first person to prove that water is a compound of hydrogen and oxygen.

Some experts believe that hydrogen forms more compounds than any other element. These compounds include water, sucrose (table sugar), alcohols, vinegar (acetic acid), household lye (sodium hydroxide), drugs, fibers, dyes, plastics, and fuels

Discovery and Naming