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Transactinide
Superheavy elements, also known as transactinide elements, transactinides, or super-heavy elements, are the chemical elements with atomic number greater than 103. The superheavy elements are those beyond the actinides in the periodic table; the last actinide is lawrencium (atomic number 103). By definition, superheavy elements are also transuranium elements, i.e., having atomic numbers greater than that of uranium (92). Depending on the definition of group 3 adopted by authors, lawrencium may also be included to complete the 6d series. Glenn T. Seaborg first proposed the actinide concept, which led to the acceptance of the actinide series. He also proposed a transactinide series ranging from element 104 to 121 and a superactinide series approximately spanning elements 122 to 153 (although more recent work suggests the end of the superactinide series to occur at element 157 instead). The transactinide seaborgium was named in his honor. Superheavy elements are radioactive and ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meitnerium
Meitnerium is a Synthetic element, synthetic chemical element with the Symbol (chemistry), symbol Mt and atomic number 109. It is an extremely radioactive synthetic element (an element not found in nature, but can be created in a laboratory). The most stable known isotope, meitnerium-278, has a half-life of 4.5 seconds, although the unconfirmed meitnerium-282 may have a longer half-life of 67 seconds. The GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany, first created this element in 1982. It is named after Lise Meitner. In the periodic table, meitnerium is a d-block transactinide element. It is a member of the period 7 element, 7th period and is placed in the group 9 elements, although no chemical experiments have yet been carried out to confirm that it behaves as the heavier homology (chemistry), homologue to iridium in group 9 as the seventh member of the 6d series of transition metals. Meitnerium is calculated to have similar properties to its lighter homolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seaborgium
Seaborgium is a synthetic chemical element with the symbol Sg and atomic number 106. It is named after the American nuclear chemist Glenn T. Seaborg. As a synthetic element, it can be created in a laboratory but is not found in nature. It is also radioactive; the most stable known isotope, 269Sg, has a half-life of approximately 14 minutes. In the periodic table of the elements, it is a d-block transactinide element. It is a member of the 7th period and belongs to the group 6 elements as the fourth member of the 6d series of transition metals. Chemistry experiments have confirmed that seaborgium behaves as the heavier homologue to tungsten in group 6. The chemical properties of seaborgium are characterized only partly, but they compare well with the chemistry of the other group 6 elements. In 1974, a few atoms of seaborgium were produced in laboratories in the Soviet Union and in the United States. The priority of the discovery and therefore the naming of the element was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Element
A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler substances by any chemical reaction. The number of protons in the nucleus is the defining property of an element, and is referred to as its atomic number (represented by the symbol ''Z'') – all atoms with the same atomic number are atoms of the same element. Almost all of the baryonic matter of the universe is composed of chemical elements (among rare exceptions are neutron stars). When different elements undergo chemical reactions, atoms are rearranged into new compounds held together by chemical bonds. Only a minority of elements, such as silver and gold, are found uncombined as relatively pure native element minerals. Nearly all other naturally occurring elements occur in the Earth as compounds or mixtures. Air is primarily a mixture o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinide Concept
In nuclear chemistry, the actinide concept proposed that the actinides form a second inner transition series homologous to the lanthanides. Its origins stem from observation of lanthanide-like properties in transuranic elements in contrast to the distinct complex chemistry of previously known actinides. Glenn T. Seaborg, one of the researchers who synthesized transuranic elements, proposed the actinide concept in 1944 as an explanation for observed deviations and a hypothesis to guide future experiments. It was accepted shortly thereafter, resulting in the placement of a new actinide series comprising elements 89 (actinium) to 103 (lawrencium) below the lanthanides in Dmitri Mendeleev's periodic table of the elements. Origin In the late 1930s, the first four actinides (actinium, thorium, protactinium, and uranium) were known. They were believed to form a fourth series of transition metals, characterized by the filling of 6 d orbitals, in which thorium, protactinium, and uranium w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heavy Element
upright=1.2, Crystals of osmium, a heavy metal nearly twice as dense as lead">lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals are generally defined as metals with relatively high density, densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author and context. In metallurgy, for example, a heavy metal may be defined on the basis of density, whereas in physics the distinguishing criterion might be atomic number, while a chemist would likely be more concerned with chemical property, chemical behaviour. More specific definitions have been published, but none of these have been widely accepted. The definitions surveyed in this article encompass up to 96 out of the 118 known chemical elements; only mercury, lead and bismuth meet all of them. Despite this lack of agreement, the term (plural or singular) is widely used in s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rutherfordium
Rutherfordium is a chemical element with the symbol Rf and atomic number 104, named after New Zealand-born British physicist Ernest Rutherford. As a synthetic element, it is not found in nature and can only be made in a laboratory. It is radioactive; the most stable known isotope, 267Rf, has a half-life of about 48 minutes. In the periodic table, it is a d-block element and the second of the fourth-row transition elements. It is in period 7 and is a group 4 element. Chemistry experiments have confirmed that rutherfordium behaves as the heavier homolog to hafnium in group 4. The chemical properties of rutherfordium are characterized only partly. They compare well with the other group 4 elements, even though some calculations had indicated that the element might show significantly different properties due to relativistic effects. In the 1960s, small amounts of rutherfordium were produced at Joint Institute for Nuclear Research in the Soviet Union and at Lawrence Berkeley National Lab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transuranium Element
The transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92, which is the atomic number of uranium. All of these elements are unstable and decay radioactively into other elements. With the exception of neptunium and plutonium (which have been found in trace amounts in nature), all do not occur naturally on Earth and are synthetic. Overview 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superactinide Series
An extended periodic table theorises about chemical elements beyond those currently known in the periodic table and proven. , the element with the highest atomic number known is oganesson (''Z'' = 118), which completes the seventh period (row) in the periodic table. All elements in the eighth period and beyond thus remain purely hypothetical. Elements beyond 118 will be placed in additional periods when discovered, laid out (as with the existing periods) to illustrate periodically recurring trends in the properties of the elements concerned. Any additional periods are expected to contain a larger number of elements than the seventh period, as they are calculated to have an additional so-called ''g-block'', containing at least 18 elements with partially filled g- orbitals in each period. An ''eight-period table'' containing this block was suggested by Glenn T. Seaborg in 1969. The first element of the g-block may have atomic number 121, and thus would have the systematic name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lawrencium
Lawrencium is a synthetic chemical element with the symbol Lr (formerly Lw) and atomic number 103. It is named in honor of Ernest Lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements. A radioactive metal, lawrencium is the eleventh transuranic element and the last member of the actinide series. Like all elements with atomic number over 100, lawrencium can only be produced in particle accelerators by bombarding lighter elements with charged particles. Fourteen isotopes of lawrencium are currently known; the most stable is 266Lr with half-life 11 hours, but the shorter-lived 260Lr (half-life 2.7 minutes) is most commonly used in chemistry because it can be produced on a larger scale. Chemistry experiments confirm that lawrencium behaves as a heavier homology (chemistry), homolog to lutetium in the periodic table, and is a valence (chemistry), trivalent element. It thus could also be classified as the first of the 7th-period tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superactinide
An extended periodic table theorises about chemical elements beyond those currently known in the periodic table and proven. , the element with the highest atomic number known is oganesson (''Z'' = 118), which completes the seventh period (row) in the periodic table. All elements in the eighth period and beyond thus remain purely hypothetical. Elements beyond 118 will be placed in additional periods when discovered, laid out (as with the existing periods) to illustrate periodically recurring trends in the properties of the elements concerned. Any additional periods are expected to contain a larger number of elements than the seventh period, as they are calculated to have an additional so-called ''g-block'', containing at least 18 elements with partially filled g- orbitals in each period. An ''eight-period table'' containing this block was suggested by Glenn T. Seaborg in 1969. The first element of the g-block may have atomic number 121, and thus would have the systematic name unb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory (LLNL) is a federal research facility in Livermore, California, United States. The lab was originally established as the University of California Radiation Laboratory, Livermore Branch in 1952 in response to the detonation of the first atomic bomb by the Soviet Union during the Cold War. It later became autonomous in 1971 and was designated a national laboratory in 1981. A federally funded research and development center, Lawrence Livermore Lab is primarily funded by the U.S. Department of Energy and it is managed privately and operated by Lawrence Livermore National Security, LLC (a partnership of the University of California), Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System. In 2012, the laboratory had the synthetic chemical element livermorium (element 116) named after it. Overview LLNL is self-described as a "premier research and development institution for sci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry World
''Chemistry World'' is a monthly chemistry news magazine published by the Royal Society of Chemistry. The magazine addresses current events in world of chemistry including research, international business news and government policy as it affects the chemical science community, plus the best product applications. It features regular columns by Philip Ball, Derek Lowe, Andrea Sella, Raychelle Burks, Alice Motion and Vanessa Seifert. The magazine is sent to all members of the Royal Society of Chemistry and is included in the cost of membership. In August 2016, the magazine began offering a "soft" paywall option, where a limited amount of content is made available free to all unregistered readers. According to the ''Journal Citation Reports'', the journal has a 2011 impact factor of 0.159, ranking it 146th out of 154 journals in the category "Chemistry, Multidisciplinary". History In 1965 two British chemistry institutions, the Chemical Society and the Royal Institute of Chemistr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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