Periodic table with elements colored according to the half-life of their most stable isotope.
Elements which contain at least one stable isotope.
Slightly radioactive elements: the most stable isotope is very long-lived, with a half-life of over two million years.
Significantly radioactive elements: the most stable isotope has half-life between 800 and 34,000 years.
Radioactive elements: the most stable isotope has half-life between one day and 130 years.
Highly radioactive elements: the most stable isotope has half-life between several minutes and one day.
Extremely radioactive elements: the most stable isotope has half-life less than several minutes.
Of the elements with atomic numbers 1 to 92, most can be found in nature, having stable isotopes (such as hydrogen) or very long-lived radioisotopes (such as uranium), or existing as common decay products of the decay of uranium and thorium (such as radon). The exceptions are elements 43, 61, 85, and 87; all four occur in nature, but only in very minor branches of the uranium and thorium decay chains, and thus all save element 87 were first discovered by synthesis in the laboratory rather than in nature (and even element 87 was discovered from purified samples of its parent, not directly from nature).
All the elements with higher atomic numbers have been first discovered in the laboratory, with neptunium and plutonium later also discovered in nature. They are all radioactive, with a half-life much shorter than the age of the Earth, so any primordial atoms of these elements, if they ever were present at the Earth's formation, have long since decayed. Trace amounts of neptunium and plutonium form in some uranium-rich rock, and small amounts are produced during atmospheric tests of nuclear weapons. These two elements are generated from neutron capture in uranium ore with subsequent beta decays (e.g. 238U + n → 239U → 239Np → 239Pu).
All elements heavier than plutonium are entirely synthetic; they are created in nuclear reactors or particle accelerators. The half lives of these elements show a general trend of decreasing as atomic numbers increase. There are exceptions, however, including several isotopes of curium and dubnium. Some heavier elements in this series, around atomic numbers 110–114, are thought to break the trend and demonstrate increased nuclear stability, comprising the theoretical island of stability.
Heavy transuranic elements are difficult and expensive to produce, and their prices increase rapidly with atomic number. As of 2008, the cost of weapons-grade plutonium was around $4,000/gram, and californium exceeded $60,000,000/gram.Einsteinium is the heaviest element that has been produced in macroscopic quantities.
Transuranic elements that have not been discovered, or have been discovered but are not yet officially named, use IUPAC's systematic element names. The naming of transuranic elements may be a source of controversy.
102. nobelium, No, named after Alfred Nobel (1958). This discovery was also claimed by the JINR, which named it joliotium (Jl) after Frédéric Joliot-Curie. IUPAC concluded that the JINR had been the first to convincingly synthesise the element, but retained the name nobelium as deeply entrenched in the literature.
105. dubnium, Db, an element that is named after the city of Dubna, where the JINR is located. Originally named "hahnium" (Ha) in honor of Otto Hahn by the Berkeley group (1970) but renamed by the International Union of Pure and Applied Chemistry (1997). This discovery was also claimed by the JINR, which named it nielsbohrium (Ns) after Niels Bohr. IUPAC concluded that credit should be shared.
106. seaborgium, Sg, named after Glenn T. Seaborg. This name caused controversy because Seaborg was still alive, but eventually became accepted by international chemists (1974). This discovery was also claimed by the JINR. IUPAC concluded that the Berkeley team had been the first to convincingly synthesise the element.
107. bohrium, Bh, named after the Danish physicist Niels Bohr, important in the elucidation of the structure of the atom (1981). This discovery was also claimed by the JINR. IUPAC concluded that the GSI had been the first to convincingly synthesise the element. The GSI team had originally proposed nielsbohrium (Ns) to resolve the naming dispute on element 105, but this was changed by IUPAC as there was no precedent for using a scientist's first name in an element name.
108. hassium, Hs, named after the Latin form of the name of Hessen, the German Bundesland where this work was performed (1984). This discovery was also claimed by the JINR. IUPAC concluded that the GSI had been the first to convincingly synthesise the element, while acknowledging the pioneering work at the JINR.
110. darmstadtium, Ds, named after Darmstadt, Germany, the city in which this work was performed (1994). This discovery was also claimed by the JINR, which proposed the name becquerelium after Henri Becquerel, and by the LBNL, which proposed the name hahnium to resolve the dispute on element 105 (despite having protested the reusing of established names for different elements). IUPAC concluded that the GSI had been the first to convincingly synthesize the element.
113. nihonium, Nh, named after Japan (Nihon in Japanese) where the element was discovered (2004). This discovery was also claimed by the JINR. IUPAC concluded that RIKEN had been the first to convincingly synthesise the element.
Superheavy elements, (also known as superheavy atoms, commonly abbreviated SHE) usually refer to the transactinide elements beginning with rutherfordium (atomic number 104). They have only been made artificially, and currently serve no practical purpose because their short half-lives cause them to decay after a very short time, ranging from a few minutes to just a few milliseconds (except for dubnium, which has a half life of over a day), which also makes them extremely hard to study.
Superheavy atoms have all been created since the latter half of the 20th century, and are continually being created during the 21st century as technology advances. They are created through the bombardment of elements in a particle accelerator. For example, the nuclear fusion of californium-249 and carbon-12 creates rutherfordium-261. These elements are created in quantities on the atomic scale and no method of mass creation has been found.
Transuranium elements may be utilized to synthesize other superheavy elements. Elements of the island of stability have potentially important military applications, including the development of compact nuclear weapons. The potential everyday applications are vast; the element americium is utilized in devices like smoke detectors and spectrometers.
^Silva, Robert J. (2006). "Fermium, Mendelevium, Nobelium and Lawrencium". In Morss, Lester R.; Edelstein, Norman M.; Fuger, Jean (eds.). The Chemistry of the Actinide and Transactinide Elements (Third ed.). Dordrecht, The Netherlands: Springer Science+Business Media. ISBN978-1-4020-3555-5.