What Type of Element Is Helium?

The element helium is one of the noble gases listed in column 18 -- formerly column VIIIA -- of the periodic table of the elements. Because it's less dense than air, this unreactive, colorless and odorless gas commonly provides buoyancy for children's balloons and giant airships. In its supercooled liquid state, helium plays an important role in magnetic resonance imaging, which allows medical professionals to diagnose illnesses that previously required exploratory surgery.

Atomic Structure

Helium has two protons in its nucleus. In its neutral state, it has two electrons in its electron cloud. The most common helium isotope, helium-4, has two neutrons. Helium-3 is the only other stable helium isotope; it contains one neutron, and accounts for approximately one out of every million helium atoms in Earth's atmosphere.

Noble Gas

Helium is the first and lightest of the noble gases, and therefore appears at the top of the periodic table's right-hand column. Like other noble gases, helium has a full outermost electron shell, which means that it does not easily form compounds. On Earth, helium occurs as a pure substance, and is commercially produced from natural gas deposits.

Sun's Energy

Although the quantity of helium in Earth's crust and atmosphere is comparatively small, helium is a major component of the known universe. Stars, including the sun, produce helium through hydrogen fusion, which releases tremendous amounts of energy. As stars near the end of their life and their hydrogen fuel reserves run out, helium fuses to form heavier elements, such as carbon and oxygen.

Discovery

Since helium does not readily form compounds, its discovery eluded chemists until 1868, when the French astronomer Pierre-Jules-Cesar Janssen observed an abnormality in the sun's spectrum during a solar eclipse. In 1870, the English astronomer Sir Norman Lockyer identified this abnormality as a new element, and derived its name from "Helios," the Greek word for the sun.