Helium: Element Properties

Helium is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements. It is the second lightest and second most abundant element in the observable universe. It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and in Jupiter. This is due to the very high nuclear binding energy of helium-4, with respect to the next three elements after helium. It binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. Most helium in the universe is helium-4, the vast majority of which was formed during the Big Bang. Large amounts of new helium are being created by nuclear fusion of hydrogen in stars.


Atomic Number: 2

Atomic Weight: 4.002602

Melting Point: 0.95 K (-272.2°C or -458.0°F)

Boiling Point: 4.22 K (-268.93°C or -452.07°F)

Density: 0.0001785 grams per cubic centimeter

Phase at Room Temperature: Gas


The formal discovery of the element was made in 1895 by two Swedish chemists, Per Teodor Cleve and Nils Abraham Langlet. Large reserves of helium were found in natural gas fields in parts of the United States in 1903, which is by far the largest supplier of the gas today.

It’s makes up about 0.0005% of the earth’s atmosphere. This trace amount of helium is not gravitationally bound to the earth and is constantly lost to space. The earth’s atmospheric helium is replaced by the decay of radioactive elements in the earth’s crust. Alpha decay, one type of radioactive decay, produces particles called alpha particles. An alpha particle can become a helium atom once it captures two electrons from its surroundings.

Uses of Helium Element

It is used to inflate blimps, scientific balloons and party balloons. It is used as an inert shield for arc welding, to pressurize the fuel tanks of liquid fueled rockets and in supersonic wind tunnels. It is combined with oxygen to create a nitrogen free atmosphere for deep sea divers so that they will not suffer from a condition known as nitrogen narcosis.