The fact that atoms never like to be alone is perhaps the first thing you learn from oxygen, where you always write O₂. Other examples are Fluorine, Chlorine and Bromine. In the case of Phosphorus and Sulphur, even more than two atoms join together. This is completely different with the noble gases. They occur to about one percent in the air.

On the periodic table, they appear on the far right in the 18th row, with helium at the top (atom model pictured above). It is the second most abundant element in the universe after hydrogen. The Big Bang theory assumes that there were only these two elements and that all the rest were created afterwards by nuclear fusion.

It is less common in automotive technology, more so in early aviation. Because of import restrictions, German airships once rose into the air with extremely flammable hydrogen, instead of being filled with Helium, which was just as extremely unreactive. Remember the accident of the Hindenburg when landing in Lakehurst (New Jersey) in 1937 with 36 dead people.

True to the periodic table, the two elements are also very far apart because of their opposite properties. Although neon was not of great importance in cars, it had an enormous importance in fluorescent tubes in the home before it was replaced by the noble gas xenon, which is now also used in cars.

The two in between are also known as so-called protective gases, e.g. argon in welding technology. This means the highest level of inertness of reaction, which is what is sought after as a filler for lamps, because otherwise the filament would be attacked, for example. Only with protective gas instead of air is it spared.

Anyone who would like to have an explanation of the still widespread halogen light is referred to the entire elements of the neighboring series 17, which are summarized under the term 'halogens'. Incidentally, 'helium' is the ancient Greek term for 'sun' because it was first discovered in the solar spectrum.

In order to explain the inertness of reaction, we now have to exclude helium, because it is the only noble gas whose outermost shell is not completely filled. So there is neither an exchange of electrons nor a formation of electron pairs.