The periodic table of elements and the island of stability.

"Moscovium and nihonium have been identified as more reactive than flerovium, demonstrating the significance of relativistic effects in superheavy elements." (ScitechDaily, The Periodic Table Just Got Wilder: Scientists Unveil the Secrets of the Heaviest Element Ever – Moscovium)

The main question is when the periodic table of elements ends. Researchers made superheavy elements that existence is measured in microseconds. The synthetic element moscovium or element number 115, has last confirmed existence time. The heaviest known element 118, the oganesson. That element is so unstable that researchers cannot measure its abilities. And maybe the heaviest known element is a noble gas. The superheavy elements are extremely unstable elements. Whose existence remains only less than a second. In the world only a couple of atoms. 

The reason why researchers work with new synthetic elements is that those elements can theoretically give solutions for nuclear reactor problems. It's possible that those, still unconfirmed elements are nuclear elements that divide into non-radioactive elements. And if those things are the fission products of some still unknown element, that thing can solve nuclear energy's worst problem which is the radioactive waste. The superheavy elements allow to creation of the ping pong-ball size nuclear reactor. That kind of reactor can give energy to the aircraft and ships.

"The height of the bars of the highlighted elements represents the strength of the bonding on a quartz surface. Credit: A. Yakushev/Ch.E. Düllmann" (ScitechDaily, The Periodic Table Just Got Wilder: Scientists Unveil the Secrets of the Heaviest Element Ever – Moscovium)

But the problem is in the short lifetime of the superheavy elements. Sometimes is introduced that the system uses time dilation so it accelerates those elements into the particle accelerators that rise their speed into the speed that is as close to the speed of light as possible. The miniature nuclear reactor can use things like antimatter. The system can turn the particles that form in the nuclear fission into antimatter particles. Another way is to drop those reactors into liquid gas. And then it could boil the liquid hydrogen. 

Source: Wikipedia, Island of stability. 

The thing that can solve the problem is the element that is in the hypothetical "Islan of stability".  

The term means the "island" of the stable superheavy isotopes. The thing that makes researchers believe that thing is that elements 106, seaborgium, 107, hassium, 110, darmstadtium, and 111, roentgenium don't seem to follow the logical line. You can see from the table that the heavier elements will suddenly have a longer divide time than the lighter ones. That lifetime curve causes an idea that there are stable superheavy elements behind, including element 126, that have not been detected yet. Researchers calculated the magical numbers of nuclei that can tell where the long-living superheavy isotopes are lurking.

"The fermium isotopes studied by laser spectroscopy are highlighted. Credit: S. Raeder" (Where Does the Periodic Table End? Exploring the Mysteries of Superheavy Elements)

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"The composition of a nuclide (atomic nucleus) is defined by the number of protons Z and the number of neutrons N, which sum to mass number" (Wikipedia, Island of Stability). 

The magic numbers mean that a certain number of protons and neutrons make the superheavy isotope or element very long-living. 

"As early as 1914, the possible existence of superheavy elements with atomic numbers well beyond that of uranium—then the heaviest known element—was suggested, when German physicist Richard Swinne proposed that superheavy elements around Z = 108 were a source of radiation in cosmic rays. Although he did not make any definitive observations, he hypothesized in 1931 that transuranium elements around Z = 100 or Z = 108 may be relatively long-lived and possibly exist in nature. In 1955, American physicist John Archibald Wheeler also proposed the existence of these elements; he is credited with the first usage of the term "superheavy element" in a 1958 paper published with Frederick Werner. " (Wikipedia, Island of Stability) 

"Three-dimensional rendering of the island of stability around N = 178 and Z = 112" (Wikipedia, Island of stability)

"This idea did not attract wide interest until a decade later, after improvements in the nuclear shell model. In this model, the atomic nucleus is built up in "shells", analogous to electron shells in atoms. Independently of each other, neutrons and protons have energy levels that are normally close together, but after a given shell is filled, it takes substantially more energy to start filling the next. Thus, the binding energy per nucleon reaches a local maximum and nuclei with filled shells are more stable than those without. This theory of a nuclear shell model originates in the 1930s, but it was not until 1949 that German physicists Maria Goeppert Mayer and Johannes Hans Daniel Jensen et al. independently devised the correct formulation." (Wikipedia, Island of Stability) 

"The numbers of nucleons for which shells are filled are called magic numbers. Magic numbers, 2, 8, 20, 28, 50, 82, and 126 have been observed for neutrons, and the next number is predicted to be 184.  Protons share the first six of these magic numbers, and 126 has been predicted as a magic proton number since the 1940s. Nuclides with a magic number of each—such as 16O (Z = 8, N = 8), 132Sn (Z = 50, N = 82), and 208Pb (Z = 82, N = 126)—are referred to as "doubly magic" and are more stable than nearby nuclides as a result of greater binding energies." (Wikipedia, Island of Stability) 

So, the most long-living isotopes would be flerovium-298, unbinilium-304 (eka-activium, element 121), and unbihexium-310 (eka-plutonium, element 126). The two last ones have not been produced yet. The island of stability is the thing that can change everything in nuclear technology. If those synthetic elements 121 and 126 are possible to produce they open the road to the skies. Those things allow them to make small nuclear reactors or pocket-size atom bombs. 

https://physics.aps.org/articles/v17/150

https://royalsocietypublishing.org/doi/10.1098/rsta.2019.0535

https://scitechdaily.com/the-periodic-table-just-got-wilder-scientists-unveil-the-secrets-of-the-heaviest-element-ever-moscovium/

https://scitechdaily.com/where-does-the-periodic-table-end-exploring-the-mysteries-of-superheavy-elements/

https://en.wikipedia.org/wiki/Island_of_stability

Element list: 

https://en.wikipedia.org/wiki/Bohrium

https://en.wikipedia.org/wiki/Darmstadtium

https://en.wikipedia.org/wiki/Hassium

https://en.wikipedia.org/wiki/Moscovium

https://en.wikipedia.org/wiki/Nihonium

https://en.wikipedia.org/wiki/Oganesson

https://en.wikipedia.org/wiki/Seaborgium

https://en.wikipedia.org/wiki/Unbihexium

https://en.wikipedia.org/wiki/Unbiunium