The periodic table, a foundational tool in chemistry, organizes all known elements based on their atomic number, electron configuration, and chemical properties. While it appears as a fixed chart, it is a dynamic scientific document, continuously evolving with new discoveries. The addition of new elements expands our understanding of matter and the fundamental building blocks of the universe, highlighting the persistent nature of scientific inquiry.
The Latest Elements to Join the Periodic Table
The four most recent elements to receive official recognition from the International Union of Pure and Applied Chemistry (IUPAC) in 2016 completed the seventh row of the periodic table. These synthetic, superheavy elements are Nihonium (Nh), Moscovium (Mc), Tennessine (Ts), and Oganesson (Og). Nihonium, with an atomic number of 113, was discovered by researchers in Japan. Moscovium, atomic number 115, and Tennessine, atomic number 117, were discovered through collaborations involving Russian and American scientists. Oganesson, with an atomic number of 118, also resulted from a collaborative effort between Russian and American teams.
Creating New Elements in the Lab
Creating new, superheavy elements involves a complex process within specialized facilities. Scientists use particle accelerators to achieve nuclear fusion, smashing lighter atomic nuclei together to form a new, heavier element. For example, the synthesis of Oganesson (element 118) involved fusing calcium-48 with californium-249. The challenge is the extremely low probability of successful fusion reactions. New atoms typically exist for only a fleeting moment, often decaying within fractions of a second, making their detection and study a significant scientific feat that often requires weeks of experimentation to produce even a single atom.
How New Elements Get Their Names
The International Union of Pure and Applied Chemistry (IUPAC) oversees the naming of new elements. After discovery verification, discoverers propose a name and symbol to IUPAC, which reviews and formally approves it after a public period. Element names must adhere to specific criteria, allowing them to be named after:
A mythological concept or character
A mineral
A place or geographical region
A property of the element
A scientist
Nihonium (Nh) was named after “Nihon,” one of the Japanese words for Japan, honoring the country where it was discovered. Moscovium (Mc) was named after the Moscow region, recognizing its discovery location, while Tennessine (Ts) acknowledges the significant contributions of research laboratories in the Tennessee region. Oganesson (Og) was named in honor of Professor Yuri Oganessian, a Russian nuclear physicist known for his pioneering work in superheavy element research.
Unveiling the Properties of Superheavy Elements
Superheavy elements are characterized by extreme instability and very short half-lives. A half-life is the time it takes for half of the atoms in a radioactive isotope sample to decay. For these elements, half-lives range from milliseconds to microseconds, making direct study of their chemical and physical properties difficult. Much about their predicted properties comes from theoretical models and extrapolations based on lighter elements.
Scientists are particularly interested in the theoretical concept of the “island of stability,” a region where certain superheavy elements are predicted to have significantly longer half-lives. This increased stability is thought to occur due to specific “magic numbers” of protons and neutrons within the atomic nucleus, creating more stable nuclear configurations. The search for this island of stability continues to drive nuclear physics research, offering new insights into the limits of the periodic table.