What is Helium?
Helium is the 2nd lightest and most common element in the universe. It is at the top of the noble gas group on the periodic table.
Characteristics and Properties
At room temperature, helium is an odorless, tasteless, and colorless gas. It has very low boiling and melting points, which means it is usually found in the gas phase, except under the most extreme conditions. Helium is the only element that does not solidify under normal pressure and remains liquid even at absolute zero.
Helium is one of the inert or rare gases. This means that its outer electron shell is filled with electrons. This makes it very non-reactive and non-flammable.
Highlights of Helium:
| Symbol | He |
| Atomic Number | 2 |
| Atomic Weight | 4.00260 |
| Classification | A noble gas and a nonmetal |
| Phase at Room Temperature | Gas |
| Density | 0.1786 g/L @ 0°C |
| Melting Point | 272.20°C, -457.96°F |
| Boiling Point | 268.93°C, -452.07°F |
| Discovered by | Pierre Janssen in 1868 |
Where is Helium found on Earth?
Helium is quite rare on Earth. There is very little of it in Earth’s atmosphere because it is so light that it eventually escapes into space.
Scientists believe that most of the helium in the universe was created during the formation of the universe. However, new helium is produced at the centers of stars and is also part of radioactive decay on Earth. Helium from radioactive decay can be found trapped underground in natural gas storage tanks.
Stars
Helium is continuously produced in the inner cores of stars. Deep inside a star, extreme pressure causes hydrogen atoms to turn into helium atoms. This produces the energy, heat, and light that powers the stars and the sun. This transformation is called nuclear fusion.
How is Helium used today?
Helium is used in balloons and airships to make them float. It is not as light as hydrogen, but it is a much safer gas because hydrogen is highly flammable.
The largest industrial user of helium gas is an MRI scanner that uses the gas to cool superconducting magnets. Other uses include silicon wafers for electronics and as a shielding gas for arc welding.
How was Helium discovered?
Helium was first discovered in 1868 by astronomer Pierre Janssen. He noticed the new element while studying eclipses. This element was not found on Earth until 1895.
Where did Helium get its name?
Helium gets its name from the Greek word “helios” which means “sun”. Helios is also the name of the sun god in Greek mythology.
Isotopes
There are eight known isotopes of helium. The most abundant helium isotope, helium-4, was largely created in the early universe.
Interesting Facts about Helium
The speed of sound in helium is about three times the speed of sound in air. This causes people’s voices to become high-pitched and high-pitched when breathing in helium (note: never breathe in helium because you can suffocate if you inhale too much).
Scientists have never observed that helium bonds with another element to form compounds.
It is often mixed with oxygen in a scuba tank to dilute the oxygen. It is used in place of nitrogen because it is insoluble in the blood and leaves the human body more quickly.
In general, helium does not combine with itself to form molecules, but appears as an atom.