Artificially synthesized chemical elements are natural


What is an artificial element?


If you hear about artificial flowers or artificial hip joints, then you know what they are about: things that we know from nature are copied from other materials because they have been lost or because they become more durable that way. But are there also "artificial elements", as for example Hans Dominik predicted in his science fiction "Element 500"?

The chemists have clearly distinguished the elements from the compounds: compounds are the innumerable different substances that we find in nature. And chemists are constantly inventing new ones: Artificial connections are all around us. But all connections are made up of a few elements. These are the smallest units that can no longer be broken down chemically, the atoms. They have a tiny nucleus of positively charged protons and uncharged neutrons surrounded by a cloud of negatively charged electrons. Each element has its own name and is clearly defined by the number of its protons (atomic number Z). The number of protons and neutrons determines the weight of an element.

How did the elements come about? After the Big Bang, the elementary particles formed very quickly, and after about three minutes they came together to form neutral hydrogen atoms. In the further course of development, the first suns emerged from hydrogen clouds. The temperature in the core of a sun is so high that when two light cores collide, they can merge into a heavier one. All elements up to the atomic number Z = 26 (iron) have been incubated in a sun. Heavy elements could form when stars exploded as a supernova at the end of their life.

One can already suspect that elements in accelerators can be “made” artificially when different atoms collide with one another with very high energy. In 1937 the first artificial element was produced with the “technetium” (Z = 43), later the “promethium” with 61 protons. Both elements had long been sought in vain in nature, in which elements with a maximum of 92 protons (uranium) occur. Today, accelerators have expanded the range of elements by 25 “transuranic elements” or “super-heavy elements” (up to Z = 118), and these are always the first thing that comes to mind when one speaks of artificial elements. Of the heaviest, however, only a few, individual atoms were created.

Radioactivity was discovered in uranium in 1896. In addition to its 92 protons, it contains 146 neutrons, which soften the mutual repulsion of the protons. But there can also be more or fewer neutrons, and this is the case with all elements. Typically, nature always strives for a balance: hot coffee becomes cold and cola warm on the same table. Similarly, for each element there is the cheapest number of neutrons at which it is stable, otherwise it will decay. The more unfavorable the number of neutrons, the faster this happens: We are talking about a radioactive isotope of the element. When we manufacture artificial elements in the accelerator, they are usually not yet in equilibrium. They are radioactive and more or less quickly turn into stable isotopes. Such short-lived radioactive isotopes are very important for medicine, materials testing and research in general, and they too are man-made.

For elements from uranium onwards, there is absolutely no neutron number that leads to a stable atomic nucleus: All transuranics are unstable. Now we also understand why these atoms do not exist in nature. They may have formed together with our solar system at that time. But to this day they have long since disintegrated. “Artificial elements” are the 25 transuranic elements that do not exist in nature - no longer exist - and the many short-lived radioactive isotopes that can all be produced in nuclear reactions.