Superheavy Elements Are Disrupting the Periodic Table
In the farthest reaches of the periodic table, starting with element 104 (Rutherfordium), there are regions where things don’t go as expected. Elements like Dubnium, Seaborgium, Bohrium, and others have never been found in nature. Their nuclei, packed with protons and neutrons, break apart within moments of being created due to fission or radioactive decay.
These are called superheavy elements. The heaviest of them is Oganesson (element 118). Since it was first created in a lab in 2002, scientists have managed to synthesize only five atoms of it. Oganesson is so radioactive that it can’t be held in your hands—it’s more like heat than matter.
Researchers use ultra-fast methods to study these unknown regions of the periodic table. Here, at the edge of chemistry, atoms display amazing properties: from pumpkin-shaped nuclei to electrons that obey the laws of relativity. Studying these properties could shed light on the primordial elements created in astrophysical events like supernovas and neutron star mergers.
A poster showing the periodic table organized by the number of protons and neutrons hangs in the hallway of the Lawrence Berkeley Laboratory. This chart contains all known information about the structure and decay of atomic nuclei and their isotopes. It’s constantly updated, like a navigator’s map with new islands—where the islands are isotopes of heavy elements, visible only in particle accelerators.
The Race to Create New Elements
Rutherfordium was first synthesized in 1969 at the Berkeley Lab and at the Joint Institute for Nuclear Research in Dubna, Russia. Since then, various scientific institutes have competed to create new elements. Today, labs in Germany and Japan are also in the race. For example, element 113, named Nihonium, was first synthesized in Japan in 2004.
Research into superheavy elements continues not just for the right to name new elements, but also because theorists predict the possibility of creating elements with greater stability. Such elements could have half-lives of a year or even thousands of days, opening up new possibilities for experiments and technology.
How Superheavy Elements Are Made
Creating these elements is difficult. Scientists use beams of heavy ions directed at a target material. For example, to create Flerovium (114 protons), calcium (20 protons) is collided with plutonium (94 protons). Most of the time, the ion beam passes through the target without interaction, but in rare successful collisions, temporary new atoms are created.
These atoms are captured and measured using helium and electric fields. Scientists study their properties by observing the reactions they manage to undergo before decaying. For instance, recent data shows that Flerovium forms strong bonds with gold at room temperature, which sets it apart from noble gases.
Relativistic Effects and Unusual Chemistry
Electrons in these heavy atoms experience a powerful pull from the nucleus, causing them to move at speeds close to the speed of light. This creates relativistic effects that change the chemical behavior of the elements. As a result, heavy elements may not follow the usual chemical rules of the periodic table. Oganesson, for example, has a diffuse electron cloud, making it difficult to study.
Debates about the placement of certain elements in the periodic table are ongoing. Since 2015, a group of experts from the International Union of Pure and Applied Chemistry has been discussing where elements like Lanthanum and Actinium, as well as Lutetium and Lawrencium, should be placed. This is because relativistic effects influence the arrangement of their outer electrons.
Nuclear Shapes and the Island of Stability
In addition to chemical experiments, scientists study the shapes of superheavy element nuclei. These nuclei are often oval-shaped, and for heavier elements, they could theoretically resemble flying saucers or even bubbles. The shape of the nucleus affects its stability and can help scientists determine which combinations of protons and neutrons can exist.
There are so-called magic numbers of protons and neutrons that make nuclei more stable. For example, an “island of stability” might be reached at certain combinations of these magic numbers. However, it’s still unclear whether such combinations can keep heavy nuclei from decaying.
Interestingly, there is a theoretical possibility of nuclei existing without electron clouds, making them incapable of chemical reactions. This challenges our usual understanding of the periodic table and chemistry as a whole.
Superheavy Elements in Space
Astrophysicists also study superheavy elements in space. These elements can form through rapid neutron capture, which occurs during cataclysmic events like neutron star collisions. Observing such events, like neutron star mergers, helps us understand how heavy elements are formed.
In 2017, scientists observed a neutron star merger for the first time, detecting gravitational waves caused by the event. This confirmed the theory that the r-process occurs during such events. Researchers found lanthanoid isotopes in this event, indicating the presence of heavy elements. However, to detect superheavy elements, it’s necessary to more precisely determine the light spectra they emit and absorb.
In December 2023, astronomers reported an excess of several lighter elements—ruthenium, rhodium, palladium, and silver—in some stars. These elements may be the result of the decay of heavy or superheavy elements, suggesting the possible existence of nuclei with up to 260 protons and neutrons.
At the University of Michigan, recent research used a new, powerful rare isotope accelerator to create heavy isotopes of thulium, ytterbium, and lutetium. These isotopes can help scientists understand the processes involved in neutron capture and their role in forming heavy elements.
The Future of Superheavy Element Research
Worldwide, scientists continue to improve their methods and equipment for synthesizing and studying superheavy elements. For example, new instruments are being installed at the Lawrence Berkeley Lab for more precise measurements of the mass of individual atoms. This will provide new data on the properties and behavior of superheavy elements.
Studying superheavy elements opens new horizons for scientists in understanding chemical and nuclear processes. These artificially created elements have unique properties not found in nature. Research in this field helps scientists not only better understand the structure and behavior of matter but also sheds light on processes occurring under the most extreme conditions in the universe.
As technology and research methods improve, scientists continue to discover new aspects of superheavy elements. These discoveries may lead to new advances in science and technology, as well as help us understand the fundamental laws of nature.