"Strassmann, they detected two unusual radioactive isotopes, one with a half-life of about 2.3 days, and the other with one of around 23 minutes. McMillan identified the short-lived isotope as uranium-239, which had been reported by Hahn and Strassmann. McMillan suspected that the other was an isotope of a new, undiscovered element, with an atomic number of 93. At the time it was believed that element 93 would have similar chemistry to rhenium, so he began working with Emilio Segrè, an expert on that element from his discovery of its homolog technetium. Both scientists began their work using the prevailing"
"23-minute activity through the following reaction: This proved that the unknown radioactive source originated from the decay of uranium and, coupled with the previous observation that the source was different chemically from all known elements, proved beyond all doubt that a new element had been discovered. McMillan and Abelson published their results in a paper entitled ""Radioactive Element 93"" in the ""Physical Review"" on May 27, 1940. They did not propose a name for the element in the paper, but they soon decided on the name ""neptunium"" since Neptune is the next planet beyond Uranus in our solar system. McMillan"
"helium ions. It was named in honor of Pierre Curie and Marie Sklodowska Curie. Similarly, americium (atomic number 95) was discovered in 1944–45 by Glenn T. Seaborg, Ralph A. James, Leon O. Morgan and Albert Ghiorso, working in the Manhattan Project. By bombing plutonium neutrons in the 60-inch cyclotron at the University of California, Berkeley. It was named after the continents of America, and because it is a homologous element of europium (atomic number 63), positioned right above it. Ralph A. James Ralph Arthur James (23 September 1920 in Salt Lake City, Utah – 24 February 1973 in Alamo, California)"
"Hesperium Hesperium (also known as esperium; atomic symbol Es) was the name assigned to the element with atomic number 94, now known as plutonium. It was named in Italian ""Esperio"" after a Greek name of Italy, Hesperia, ""the land of the West"". The same team assigned the name ausonium to element 93, after Ausonia, a poetic name of Italy. By comparison, uranium, the heaviest of the primordial elements, has atomic number 92. The discovery of the element, now discredited, was claimed by Enrico Fermi and a team of scientists at the University of Rome in 1934. Following the discovery of"
"into a proton, thus moving the resulting isotope one place up the periodic table. When Fermi's team bombarded uranium, they observed this behavior as well, which strongly suggested that the resulting isotope had an atomic number of 93. Fermi was initially reluctant to publicize such a claim, but after his team observed several unknown half-lives in the uranium bombardment products that did not match those of any known isotope, he published a paper entitled ""Possible Production of Elements of Atomic Number Higher than 92"" in June 1934. In it he proposed the name ausonium (atomic symbol Ao) for element 93,"
"Uranium Uranium is a chemical element with symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all isotopes of uranium are unstable, with half-lives varying between 159,200 years and 4.5 billion years. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99%) and uranium-235 (which has 143 neutrons). Uranium has the highest atomic weight of the primordially occurring elements. Its density is"
"elements, proved beyond all doubt that a new element had been discovered. McMillan and Abelson published their results in an article entitled ""Radioactive Element 93"" in the ""Physical Review"" on May 27, 1940. They did not propose a name for the element in the article, but they soon decided on ""neptunium"", since uranium had been named after the planet Uranus, and Neptune is the next planet beyond in our solar system. McMillan suddenly departed at this point, leaving Glenn Seaborg to pursue this line of research, which led to the second transuranium element, plutonium. In 1951, McMillan shared the Nobel"
"Ausonium Ausonium (atomic symbol Ao) was the name assigned to the element with atomic number 93, now known as neptunium. It was named after a Greek name of Italy, Ausonia. The same team assigned the name hesperium to element 94, after Hesperia, a poetic name of Italy. (Element 94 was later named plutonium). The discovery of the element, now discredited, was made by Enrico Fermi and a team of scientists at the University of Rome in 1934. In the same year Ida Noddack had already presented alternative explanations for the experimental results of Fermi. Following the discovery of nuclear fission"
"through 94 are unstable to the point that radioactive decay of all isotopes can be detected. Some of these elements, notably bismuth (atomic number 83), thorium (atomic number 90), and uranium (atomic number 92), have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced the heavy metals before the formation of our Solar System. At over 1.9 years, over a billion times longer than the current estimated age of the universe, bismuth-209 (atomic number 83) has the longest known alpha decay half-life of any naturally occurring element, and is almost"
"might be capable of fission by both fast and slow neutrons like uranium-235. If so, this promised another path to an atomic bomb, as it could be bred from the more abundant uranium-238 in a nuclear reactor, and separation from uranium could be by chemical means, as it was a different element, thereby avoiding the necessity for isotope separation. Kemmer suggested that since uranium was named after the planet Uranus, element 93 could be named neptunium and 94 plutonium after the next two planets. Later it was discovered that the Americans had independently adopted the same names, following the same"
"94. McMillan agreed to the collaboration. Seaborg first reported alpha decay proportionate to only a fraction of the element 93 under observation. The first hypothesis for this alpha particle accumulation was contamination by uranium, which produces alpha-decay particles; analysis of alpha-decay particles ruled this out. Seaborg then postulated that a distinct alpha-producing element was being formed from element 93. In February 1941, Seaborg and his collaborators produced plutonium-239 through the bombardment of uranium. In their experiments bombarding uranium with deuterons, they observed the creation of neptunium, element 93. But it then underwent beta-decay, forming a new element, plutonium, with 94"
"a massive extraterrestrial object caused the extinction of dinosaurs and many other species 66 million years ago. It is thought that the total amount of iridium in the planet Earth is much higher than that observed in crustal rocks, but as with other platinum group metals, the high density and tendency of iridium to bond with iron caused most iridium to descend below the crust when the planet was young and still molten. Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term ""platina"", which is"
"so long (at least 100 million times longer than the estimated age of the universe) that their radioactive decay has yet to be detected by experiment. Elements with atomic numbers 83 through 94 are unstable to the point that their radioactive decay can be detected. Three of these elements, bismuth (element 83), thorium (element 90), and uranium (element 92) have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced the heavy elements before the formation of our solar system. For example, at over 1.9 years, over a billion times longer"
"the most common. It is released as a product of U, mainly in nuclear plants and during nuclear weapons tests in the 1950s and 1960s. It has a very long half-life (1.53 million years), its decay emits only low energy radiations, and it is not considered as highly hazardous. Zirconium Zirconium is a chemical element with symbol Zr and atomic number 40. The name ""zirconium"" is taken from the name of the mineral zircon (the word is related to Persian ""zargun"" (zircon;""zar-gun"", ""gold-like"" or ""as gold"")), the most important source of zirconium. It is a lustrous, grey-white, strong transition metal"
"element 93, which they named neptunium. The next synthetic element, plutonium, quickly followed in 1941, which scientists realized was readily able to undergo fission in a way capable of producing the desired chain reaction. It was soon being made into a bomb. A mere seven years after the discovery of nuclear fission, on 6 August 1945, half a gram of uranium was converted into energy when the world's first atomic bomb was dropped on Hiroshima. As Lisa Meitner's calculations suggested, this conversion released energy equivalent to 13,000 tons of TNT. A plutonium bomb was dropped on Nagasaki three days later."
"as a pioneer in nuclear medicine and is one of its most prolific discoverers of isotopes. In 1939 he became an instructor in chemistry at Berkeley, was promoted to assistant professor in 1941 and professor in 1945. University of California, Berkeley, physicist Edwin McMillan led a team that discovered element 93, which he named neptunium in 1940. In November, he was persuaded to leave Berkeley temporarily to assist with urgent research in radar technology. Since Seaborg and his colleagues had perfected McMillan's oxidation-reduction technique for isolating neptunium, he asked McMillan for permission to continue the research and search for element"
"to impair liver function, but the main side effects from inhalation of rare-earth oxides in humans come from radioactive thorium and uranium impurities. Praseodymium Praseodymium is a chemical element with symbol Pr and atomic number 59. It is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals. Praseodymium is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air. Praseodymium always"
"star) and ""æfensteorra"" (evening star). It was not until the 13th century C.E. that the name ""Venus"" was adopted for the planet (in classical Latin, though the morning star was considered sacred to the goddess Venus, it was called Lucifer). In Chinese the planet is called ""Jīn-xīng"" (金星), the golden planet of the metal element. It is known as ""Kejora"" in Indonesian and Malay. Modern Chinese, Japanese and Korean cultures refer to the planet literally as the ""metal star"" (), based on the Five elements. Because the movements of Venus appear to be discontinuous (it disappears due to its proximity"
"pyrophoric; small grains will ignite spontaneously in air at room temperature. Uranium metal is commonly handled with gloves as a sufficient precaution. Uranium concentrate is handled and contained so as to ensure that people do not inhale or ingest it. Uranium Uranium is a chemical element with symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all isotopes of uranium are unstable, with half-lives varying between 159,200 years and 4.5"
"Heinrich Klaproth, who named the new element after the recently discovered planet Uranus. Eugène-Melchior Péligot was the first person to isolate the metal and its radioactive properties were discovered in 1896 by Henri Becquerel. Research by Otto Hahn, Lise Meitner, Enrico Fermi and others, such as J. Robert Oppenheimer starting in 1934 led to its use as a fuel in the nuclear power industry and in ""Little Boy"", the first nuclear weapon used in war. An ensuing arms race during the Cold War between the United States and the Soviet Union produced tens of thousands of nuclear weapons that used"
"radioactive isotope uranium-239. U decays by beta emission to neptunium-239, also a beta-emitter, that decays in its turn, within a few days into plutonium-239. Pu was used as fissile material in the first atomic bomb detonated in the ""Trinity test"" on 15 July 1945 in New Mexico. In nature, uranium is found as uranium-238 (99.2742%) and uranium-235 (0.7204%). Isotope separation concentrates (enriches) the fissionable uranium-235 for nuclear weapons and most nuclear power plants, except for gas cooled reactors and pressurised heavy water reactors. Most neutrons released by a fissioning atom of uranium-235 must impact other uranium-235 atoms to sustain the"
"and Lise Meitner who were among the best radiochemists in the world at the time and supporters of Fermi's claim, but they all failed. Much later, it was determined that the main reason for this failure was because the predictions of element 93's chemical properties were based on a periodic table which lacked the actinide series. This arrangement placed protactinium below tantalum, uranium below tungsten, and further suggested that element 93, at that point referred to as eka-rhenium, should be similar to the group 7 elements, including manganese and rhenium. Thorium, protactinium, and uranium, with their dominant oxidation states of"
"element in platinum ore and in the mineral columbite. They also found rhenium in gadolinite and molybdenite. In 1928 they were able to extract 1 g of the element by processing 660 kg of molybdenite. Element 43 was named masurium (after Masuria in Eastern Prussia). The group bombarded columbite with a beam of electrons and deduced element 43 was present by examining X-ray diffraction spectrograms. The wavelength of the X-rays produced is related to the atomic number by a formula derived by Henry Moseley. The team claimed to detect a faint X-ray signal at a wavelength produced by element 43."
"of radioactivity, is named in honour of her and Pierre Curie (although the commission which agreed on the name never clearly stated whether the standard was named after Pierre, Marie or both of them). The element with atomic number 96 was named curium. Three radioactive minerals are also named after the Curies: curite, sklodowskite, and cuprosklodowskite. She received numerous honorary degrees from universities across the world. The Marie Skłodowska-Curie Actions fellowship program of the European Union for young scientists wishing to work in a foreign country is named after her. In Poland, she had received honorary doctorates from the Lwów"
"tungsten. It followed that first transuranic elements would be similar to group 7 to 10 elements, i.e. rhenium and platinoids. The Hahn group established the presence of multiple isotopes of at least four such elements, and (mistakenly) identified them as elements with atomic numbers 93 through 96. They were the first scientists to measure the half-life of U and to establish chemically that it was an isotope of uranium, but they were unable to continue this work to its logical conclusion and identify the decay product of U – namely, neptunium (the real element 93); this task was only completed"
"the periodic table. The atomic weight is 107.8682(2) u; this value is very important because of the importance of silver compounds, particularly halides, in gravimetric analysis. Both isotopes of silver are produced in stars via the s-process (slow neutron capture), as well as in supernovas via the r-process (rapid neutron capture). Twenty-eight radioisotopes have been characterized, the most stable being Ag with a half-life of 41.29 days, Ag with a half-life of 7.45 days, and Ag with a half-life of 3.13 hours. Silver has numerous nuclear isomers, the most stable being Ag (""t"" = 418 years), Ag (""t"" = 249.79"
"in 1938, it was realized that Fermi's discovery was actually a mixture of barium, krypton, and other elements. The actual element was discovered several years later, and assigned the name neptunium. Fascist authorities wanted one of the elements to be named ""littorio"" after the Roman ""lictores"" who carried the ""fasces"", a symbol appropriated by Fascism. Ausonium Ausonium (atomic symbol Ao) was the name assigned to the element with atomic number 93, now known as neptunium. It was named after a Greek name of Italy, Ausonia. The same team assigned the name hesperium to element 94, after Hesperia, a poetic name"
"most dangerous if taken into the body. In addition, californium-249 and californium-251 can cause tissue damage externally, through gamma ray emission. Ionizing radiation emitted by californium on bone and in the liver can cause cancer. Californium Californium is a radioactive chemical element with symbol Cf and atomic number 98. The element was first synthesized in 1950 at the Lawrence Berkeley National Laboratory (then the University of California Radiation Laboratory), by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that"
"4.4683 years (close to the age of the Earth). Uranium-238 is an α emitter, decaying through the 18-member uranium series into lead-206. The decay series of uranium-235 (historically called actino-uranium) has 15 members that ends in lead-207. The constant rates of decay in these series makes comparison of the ratios of parent to daughter elements useful in radiometric dating. Uranium-233 is made from thorium-232 by neutron bombardment. The isotope uranium-235 is important for both nuclear reactors and nuclear weapons because it is the only isotope existing in nature to any appreciable extent that is fissile, that is, can be broken"
"the issue and found no evidence to suggest toxicity in vivo. Platinum Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name is derived from the Spanish term ""platino"", meaning ""little silver"". Platinum is a member of the platinum group of elements and group 10 of the periodic table of elements. It has six naturally occurring isotopes. It is one of the rarer elements in Earth's crust, with an average abundance of approximately 5 μg/kg. It occurs in some nickel and copper ores along"
"Radium Radium is a chemical element with symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rather than oxygen) on exposure to air, forming a black surface layer of radium nitride (RaN). All isotopes of radium are highly radioactive, with the most stable isotope being radium-226, which has a half-life of 1600 years and decays into radon gas (specifically the isotope radon-222). When radium decays, ionizing radiation is a product, which can excite fluorescent"
"Platinum Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name is derived from the Spanish term ""platino"", meaning ""little silver"". Platinum is a member of the platinum group of elements and group 10 of the periodic table of elements. It has six naturally occurring isotopes. It is one of the rarer elements in Earth's crust, with an average abundance of approximately 5 μg/kg. It occurs in some nickel and copper ores along with some native deposits, mostly in South Africa, which accounts for"
"Californium Californium is a radioactive chemical element with symbol Cf and atomic number 98. The element was first synthesized in 1950 at the Lawrence Berkeley National Laboratory (then the University of California Radiation Laboratory), by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium). The element was named after the university and the state of California. Two crystalline forms exist for californium under normal"