Element 118 created
A research team from the United States and Russia has succeeded in synthesizing the chemical element with atomic number 118 for the first time. It is thus the heaviest representative in the periodic table and is located at the bottom right under the noble gas radon. The element bears the provisional name Ununoctium (from Latin un-un-octo: "one-one-eight") or Eka-Radon (from Sanskrit eka: "one"; as well as radon).
The experts are still arguing about whether it really behaves chemically like an inert gas due to its complex structure. Until now, the experimenters have only been able to produce three individual atoms of this new substance and have not been able to carry out any chemical reactions with them.
The atomic number 118 indicates that there are just as many protons in the nucleus. Only values smaller than or equal to 92 (uranium) occur in nature – heavier atomic nuclei are highly radioactive and quickly decay into lighter ones. So if these materials ever existed at the beginning of the universe, they are gone by now.
But heavy elements can be artificially generated in particle accelerators designed for this purpose. To do this, experimenters bombard targets made of one type of atom with projectiles from another. The Russian-American team bombarded their sample of the - also artificial - element californium, which contains 98 protons, with calcium ions. They stripped off all their electrons beforehand in order to be able to accelerate them to a suitable energy using electric fields. This is necessary so that the atomic nuclei, despite their mutual electrostatic repulsion - both nucleons are strongly positively charged because of the protons in the nucleus - come close enough to fuse with each other. The new radioactive element that has a half-life of less than a millionth of a second has now emerged from these experiments. It betrayed its existence by its typical radioactive decay into lighter atomic nuclei.
The scientists hope that their experiments will one day lead to what is known as an island of stability. Depending on the number and ratio of protons and neutrons in the atomic nucleus, according to the physical theory that explains their cohesion, the radioactive nuclei should become more stable once they reach a certain size. In particular, so-called magic numbers play a role, which, according to a model, lead to closed shells and thus to particularly stable configurations. Some researchers believe the "coast" of this island begins with the now-manufactured element atomic number 118.
