Scientists have added four new elements to the Periodic Table

Less than one hundred elements compose our entire world. Hydrogen, iron, carbon, gold, and oxygen are some of the elements that make up the universe – from the Sun and the other stars, to computers, plants, bicycles, and animals.

In 1869, when the Russian scientist Dmitri Mendeleev published a table in which the elements are arranged according to their properties. Many of them had yet to be discovered, but Mendeleev believed that they existed because of the gaps in his table. The “missing” elements were discovered one by one, and the table was completed in the 1940s, when scientists managed to split the atom and understand that we can create new elements through nuclear reactions.

 

The updated periodic table. Illustration from Shutterstock

Eventually, it turned out that even the hardest elements to discover, which were created in laboratories, do exist naturally, but in tiny amounts. This was true up to uranium, atomic number 92 (which means there are 92 protons in its nucleus). Just as scientists were discovering the “missing” elements, scientists also started to ask themselves what would happen if they tried to create elements that were heavier than uranium – elements that did not exist in nature.

And so, in 1940, scientists from the University of California, Berkeley, used a particle accelerator to create a new element with 93 protons (neptunium), and shortly thereafter, an element with the atomic number of 94, which was slightly more stable – plutonium. It would later be discovered that plutonium does exist naturally in minute quantities, but this fact, along with information about the discovery of plutonium itself, was kept secret for years, because of its use in the production of nuclear bombs.

As knowledge expanded and particle accelerator technology improved, scientists managed to artificially create more and more heavy elements: They took relatively heavy elements and collided them at incredibly high force. The collisions yielded the nuclei of even heavier elements. The problem is that most of these nuclei are not stable and disintegrate or decay in milliseconds. In some cases, the scientists could not even capture the atoms of these elements, but only conclude that they fleetingly existed because of what remained after they degraded.

The heavier an element’s nucleus, the harder it is to create it in a laboratory, so discovering new elements became increasingly difficult. In the 1980s and 1990s, scientists created six new elements (atomic numbers 107-112), and only in 2011, did the International Union of Pure and Applied Chemistry (IUPAC) approve the existence of two additional elements – atomic numbers 114 and 116. IUPAC also spent years looking into the four “missing” elements in the periodic table’s bottom row, and, in 2016, confirmed the discovery of the missing four.

Element 113 was created by researchers at Japan’s Riken institute, who named it Nihonium after the common Japanese name for Japan, Nihon. The discovery of elements 115 and 117 was achieved thanks to a collaboration between the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, the American Lawrence Livermore National Laboratory in California, and the Oak Ridge National Laboratory in Tennessee. The former two institutions also discovered element 118, the heaviest one to be discovered to date.

The race is still on to discover the next elements. Many physicists believe that it is possible to create elements 119 and 120, but for additional elements beyond that, it seems that the repulsion between the protons outweighs the nuclear power holding them together, and such elements cannot exist, even for a split second.

 

 

 

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