Helium is the second element on the periodic table. It contains 2 protons and 2 electrons, and It forms up to 35% of our universe.
Where can we find helium atom ?
Helium atom is very rare on the planet Earth. In fact, It’s the only element in the periodic table that it was discovered outside our planet. Scientists discover its existence when they were looking to the sun and they noticed a bright yellow line. This yellow line is due to the excitation of the electrons in the helium atom.
Because this atom was found on the Sun, they named it “helium” from the Greek word helios.
Helium atom was then discovered on Earth with people were examining a uranium mineral. Then a few years later, helium gas was discovered as a component of natural gas coming out of gas fields in the United States.
Helium is found associated with uranium, and with other radioactive materials, because the nucleus of helium contains two neutrons and two protons, and this nucleus is called alpha particles that are emitted during radioactive decay. So if a radioactive atom like uranium decays and emits an alpha particle, it can quickly picks up a couple of electrons and becomes an atom of helium. And over millions of years this can accumulate in gas field.
How can we use helium atom ?
Helium in the natural gas was discovered shortly before the first World War. And so it was quickly realized that this gas could be useful for observation balloons on the battlefields. And because it doesn’t burn, So if a bullet goes through the balloon it doesn’t immediately blow up.
Helium nucleus, or helium atom, Weighs four times as much as a hydrogen atom which has just one proton. But because hydrogen exists as an H2 molecule, helium atom, which is stable and doesn’t bond to another atom, weighs twice as much as a hydrogen molecule.
In our days helium gas is used to fill colourful balloons for birthday parties, because it can fly very hight due to his very small weight.
What is the most important property of helium ?
The most important property of helium is the fact that when you liquefy it, it forms the coldest liquid that one can obtain. Liquid helium boils at -269oC. So liquid helium can be used to cool materials particularly certain metals.