It is certainly possible that there are elements in the universe that we have not discovered or fully characterized yet. The periodic table of elements, which lists all known chemical elements, currently consists of 118 confirmed elements However, scientific exploration and research continue to uncover new knowledge and expand our understanding of the universe.
Discovering new elements typically involves experiments in nuclear physics and particle accelerators. Scientists create and observe synthetic or highly unstable elements with extremely short lifetimes. These elements are typically produced through nuclear reactions by bombarding heavy nuclei with particles.
In recent decades, several new elements beyond atomic number 118 have been synthesized and confirmed, such as elements 113, 115, 117, and 118. However, these superheavy synthetic elements are highly unstable and quickly decay into other elements. The search for and synthesis of new elements is an ongoing area of scientific research.
It is worth noting that the existence of stable or long-lived superheavy elements beyond those currently known is uncertain. Theoretical models suggest that an "island of stability" may exist, where elements with significantly longer lifetimes could potentially be found, but this is still an area of active investigation.
In addition to undiscovered elements, there are also various isotopes of known elements that have not yet been synthesized or fully characterized. Isotopes are variants of an element that have the same number of protons but differ in the number of neutrons. Some isotopes may be highly unstable or have very short half-lives, making their observation and study challenging.
Overall, while our current periodic table represents our current understanding of known elements, it is possible that there are still elements and isotopes in the universe that remain to be discovered or further studied. Continued scientific research and technological advancements will likely lead to further expansion of our knowledge in this area.