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  • richardmitnick 1:23 am on March 5, 2019 Permalink | Reply
    Tags: Deuterium and tritium- called heavy hydrogen have been used to make hydrogen bombs, Fusion Technology-when burned in a controlled way hydrogen offers the cleanest fuel producing only water as the waste product, , Periodic Table, Protons also are the key component of fuel cells. Rather than burn the hydrogen fuel cells convert it to electricity and are seen as the way of the future. They do this by splitting the hydrogen gas i, , With rapid advances in chemistry and engineering hydrogen stations could start to appear soon becoming as commonplace as gasoline filling stations are today.   

    From The Conversation: “Lightweight of periodic table plays big role in life on Earth” 

    Conversation
    From The Conversation

    3.3.19
    Nicholas Leadbeater

    Periodic table Sept 2017. Wikipedia

    Although hydrogen is the lightweight of the chemical elements, it packs a real punch when it comes to its role in life and its potential as a solution to some of the world’s challenges. As we celebrate the 150th anniversary of the periodic table, it seems reasonable to tip our hat to this, the first element on the table.

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    One oxygen atom is connected to two hydrogen atoms to make water. Liaskovskaia Ekaterina/SHutterstock.com

    Hydrogen is the most abundant element in the universe, but not on Earth due to its light weight, which allows the gas to just float off into space. Hydrogen is essential to our life – it fuels the sun, which converts hundreds of million tons of hydrogen into helium every second. And two hydrogen atoms are attached to one oxygen atom to make water. Both these things make our planet habitable.

    Not only does hydrogen enable the sun to warm the Earth and help create the water that sustains life, but this simplest of all the elements may also provide the key to finding a clean fuel source to power the planet.

    Hydrogen’s yin and yang as an energy source

    Like many other chemical elements, although hydrogen is of immense value to us, it also has a darker side. Being lighter than air, it makes things float, which is why is was used in early airships. But hydrogen is highly explosive, and in 1937 the German airship the Hindenburg exploded on its attempt to dock with its mooring mast after a transatlantic journey, killing 36 people.

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    Isotopes of hydrogen: protium, deuterium and tritium. Designua/Shutterstock.com

    Hydrogen’s cousins, deuterium and tritium, called heavy hydrogen, have been used to make hydrogen bombs. Here, the heavy hydrogen atoms merge together in a process called nuclear fusion to make helium, a bit like the reaction that takes place in the sun. The amount of energy produced by this process is greater than any other known process – the area at the center of the explosion is essentially vaporized, generating shock waves that destroy anything in their way. The bright white light produced can blind people many miles away. It also produces radioactive products that are carried in the air and cause widespread contamination of the environment.

    Taming the beast, however, could be the solution to the energy problems of the future. When burned in a controlled way, hydrogen offers the cleanest fuel, producing only water as the waste product. That’s refreshing when compared with a gasoline engine that produces climate change-inducing carbon dioxide and a range of other nasty gases. When stored under high pressure and very low temperature of -400 degrees Fahrenheit, hydrogen exists as a liquid, and its combustion with oxygen is used for propelling rockets into space.

    However, a car with a tank of highly explosive hydrogen rocket fuel doesn’t sound like a safe bet. There’s currently lots of research focused on solving the storage problem. Large numbers of scientists are trying to develop chemical compounds that safely hold and release hydrogen. This is actually a hard nut to crack and is something that will take time and many great minds to solve.

    The power of hydrogen

    Hydrogen atoms also give things like lemon juice and vinegar their distinctive tart taste. Positively charged hydrogen atoms, called protons, having been stripped of their only electron, float around in these solutions and are the key component of acids. The chemistry of these protons is also responsible for driving photosynthesis, the process whereby plants turn light energy into chemical energy, and powering many processes in the human body.

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    This is the symbol and electron diagram for hydrogen. BlueRingMedia/Shutterstock.com

    Protons also are the key component of fuel cells. Rather than burn the hydrogen, fuel cells convert it to electricity and are seen as the way of the future. They do this by splitting the hydrogen gas into protons and electrons on one side of the fuel cell. The positively charged protons move over to the other side of the cell, leaving behind the negatively charged electrons. This creates a flow of electricity between the sides of the cell when connected with an external circuit. This current can power an electric motor placed in this circuit. Hydrogen-powered trains are already in operation in Germany, and several international car manufacturers are developing fuel-cell powered cars. Again, the only byproduct of the process is water.

    In the future, I think we will see increasing use of hydrogen as a fuel. For it to be useful, there are two major challenges. A big one is the storage issue. Engineers need to figure out how to store hydrogen safely and start to build places where people can fill up. With rapid advances in chemistry and engineering, hydrogen stations could start to appear soon, becoming as commonplace as gasoline filling stations are today. This sort of infrastructure is going to be essential. You don’t want run out of fuel on a journey because, unlike a gas-powered car, you can’t call a friend to bring you a canister of hydrogen.

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    Hydrogen fuel pump at Shell station, for automobiles running on pollution-free hydrogen-powered fuel cells. Rob Crandall/Shutterstock.com

    See the full article here .

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    The Conversation launched as a pilot project in October 2014. It is an independent source of news and views from the academic and research community, delivered direct to the public.
    Our team of professional editors work with university and research institute experts to unlock their knowledge for use by the wider public.
    Access to independent, high quality, authenticated, explanatory journalism underpins a functioning democracy. Our aim is to promote better understanding of current affairs and complex issues. And hopefully allow for a better quality of public discourse and conversation.

     
  • richardmitnick 9:18 am on February 28, 2019 Permalink | Reply
    Tags: An element is defined by the number of protons it contains, At the far edge of the periodic table elements decay within instants of their formation offering very little time to study their properties, , , Each element comes in a variety of types known as isotopes distinguished by the number of neutrons in the nucleus, For superheavy atoms chemistry gets weird, Periodic Table, , Scientists are hoping to stretch the periodic table even further beyond tennessine and three other recently discovered elements (113 115 and 118) that completed the table’s seventh row.   

    From Science News: “Extreme elements push the boundaries of the periodic table” 

    From Science News

    February 27, 2019
    Emily Conover

    For superheavy atoms, chemistry gets weird.

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    SMASH HIT To create new elements and study the chemistry of the periodic table’s heaviest atoms, researchers at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany, use the apparatus above to create beams of ions that scientists then smash into other elements.

    GSI Helmholtz Centre for Heavy Ion Research GmbH, Darmstadt, Germany,

    The rare radioactive substance made its way from the United States to Russia on a commercial flight in June 2009. Customs officers balked at accepting the package, which was ensconced in lead shielding and emblazoned with bold-faced warnings and the ominous trefoil symbols for ionizing radiation. Back it went across the Atlantic.

    U.S. scientists enclosed additional paper work and the parcel took a second trip, only to be rebuffed again. All the while, the precious cargo, 22 milligrams of an element called berkelium created in a nuclear reactor at Oak Ridge National Laboratory in Tennessee, was deteriorating. Day by day, its atoms were decaying. “We were all a little frantic on our end,” says Oak Ridge nuclear engineer Julie Ezold.

    On the third try, the shipment cleared customs. At a laboratory in Dubna, north of Moscow, scientists battered the berkelium with calcium ions to try to create an even rarer substance. After 150 days of pummeling, the researchers spotted six atoms of an element that had never been seen on Earth. In 2015, after other experiments confirmed the discovery, element 117, tennessine, earned a spot on the periodic table (SN: 2/6/16, p. 7).

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    Scientists made radioactive berkelium at the High Flux Isotope Reactor at Oak Ridge National Laboratory in Tennessee (shown), and shipped it to Russia to be bombarded with a beam of calcium-48 to yield the superheavy element tennessine. ORNL/Flickr (CC BY 2.0)

    ORNL High Flux Isotope Reactor

    Scientists are hoping to stretch the periodic table even further, beyond tennessine and three other recently discovered elements (113, 115 and 118) that completed the table’s seventh row. Producing the next elements will require finessing new techniques using ultrapowerful beams of ions, electrically charged atoms. Not to mention the stress of shipping more radioactive material across borders.

    But questions circulating around the periodic table’s limits are too tantalizing not to make the effort. It’s been 150 years since Russian chemist Dmitrii Mendeleev created his periodic table. Yet “we still cannot answer the question: Which is the heaviest element that can exist?” says nuclear chemist Christoph Düllmann of the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany.

    At the far edge of the periodic table, elements decay within instants of their formation, offering very little time to study their properties. In fact, scientists still know little about the latest crew of newfound elements. So while some scientists are hunting for never-before-seen elements, others want to learn more about the table’s newcomers and the strange behaviors those superheavy elements may exhibit.

    For such outsized atoms, chemistry can get weird, as atomic nuclei, the hearts at the center of each atom, bulge with hundreds of protons and neutrons. Around them swirl great flocks of electrons, some moving at close to the speed of light. Such extreme conditions might have big consequences — messing with the periodic table’s tidy order, in which elements in each column are close chemical kin that behave in similar ways.

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    In Russia, scientist Vladislav Shchegolev inspects a package of berkelium after its overseas flight in 2009. The material was later used to create element 117, tennessine.
    Courtesy of ORNL.

    Scientists keep pushing these superheavy elements further as part of the search for what’s poetically known as the island of stability. Atoms with certain numbers of protons and neutrons are expected to live longer than their fleeting friends, persisting perhaps for hours rather than fractions of a second. Such an island would give scientists enough time to study those elements more closely and understand their quirks. The first glimpses of that mysterious atoll have been spotted, but it’s not clear how to get a firm footing on its shores.

    Driving all this effort is a deep curiosity about how elements act at the boundaries of the periodic table. “This might sound corny, but it’s really just [about] pure scientific understanding,” says nuclear chemist Dawn Shaughnessy of Lawrence Livermore National Laboratory in California. “We have these things that are really at the extremes of matter and we don’t understand right now how they behave.”

    Assembling atoms

    An element is defined by the number of protons it contains. Create an atom with more protons than ever before, and you’ve got yourself a brand new element. Each element comes in a variety of types, known as isotopes, distinguished by the number of neutrons in the nucleus. Changing the number of neutrons in an atom’s nucleus alters the delicate balance of forces that makes a nucleus stable or that causes it to decay quickly. Different isotopes of an element might have wildly different half-lives, the period of time it takes for half of the atoms in a sample to decay into smaller elements.

    Mendeleev’s periodic table, presented to the Russian Chemical Society on March 6, 1869, contained only 63 elements (SN: 1/19/19, p. 14). At first, scientists added to the periodic table by isolating elements from naturally occurring materials, for example, by scrutinizing minerals and separating them into their constituent parts. But that could take scientists only so far. All the elements beyond uranium (element 92) must be created artificially; they do not exist in significant quantities in nature. Scientists discovered elements beyond uranium by bombarding atoms with neutrons or small atomic nuclei or by sifting through the debris from thermonuclear weapons tests.

    But to make the heaviest elements, researchers adopted a new brute force approach: slamming beams of heavy atoms into a target, a disk that holds atoms of another element. If scientists are lucky, the atoms in the beam and target fuse, creating a new atom with a bigger, bulkier nucleus, perhaps one holding more protons than any other known.

    Researchers are using this strategy to go after elements 119 and 120. Scientists want to create such never-before-seen atoms to test how far the periodic table goes, to satisfy curiosity about the forces that hold atoms together and to understand what bizarre chemistry might occur with these extreme atoms.

    _____________________________________________________________

    How the periodic table went from a sketch to an enduring masterpiece
    150 years ago, Mendeleev perceived the relationships of the chemical elements
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    REVOLUTIONARY Russian chemist Dmitrii Mendeleev (shown around 1880) was the first to publish a periodic table, which put the known elements into a logical order and left room for elements not yet discovered. Heritage Image Partnership Ltd/Alamy Stock Photo.

    An ordered vision

    Mendeleev’s periodic table, published in 1869, was a vertical chart that organized 63 known elements by atomic weight. This arrangement placed elements with similar properties into horizontal rows. The title, translated from Russian, reads: “Draft of system of elements: based on their atomic masses and chemical characteristics.”

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    _____________________________________________________________
    The periodic table’s lineup

    The search is gearing up for the next superheavy elements, 119 and 120 (red boxes in the table below). Meanwhile, scientists are studying the known superheavy elements (blue) to better understand how such large atoms behave.

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    _____________________________________________________________

    Coaxing nuclei to combine into a new element is done only at highly specialized facilities in a few locations across the globe, including labs in Russia and Japan. Researchers carefully choose the makeup of the beam and the target in hopes of producing a designer atom of the element desired. That’s how the four newest elements were created: nihonium (element 113), moscovium (115), tennessine (117) and oganesson (118) (SN Online: 11/30/16).

    To create tennessine, for example, scientists combined beams of calcium with a target made of berkelium — once the berkelium finally made it through customs in Russia. The union makes sense when you consider the number of protons in each nucleus. Calcium has 20 protons and berkelium has 97, making for 117 protons total, the number found in tennessine’s nucleus. Combine calcium with the next element down the table, californium, and you get element 118, oganesson.

    Using calcium beams — specifically a stable calcium isotope with a combined total of 48 protons and neutrons known as calcium-48 — has been highly successful. But to create bigger nuclei would take increasingly exotic materials. The californium and berkelium used in previous efforts are so rare that the target materials had to be made at Oak Ridge, where researchers stew materials in a nuclear reactor for months and carefully process the highly radioactive product that comes out. All that work might produce just milligrams of the material.

    To discover element 119 using a calcium-48 beam, researchers would need a target made of einsteinium (element 99) which is even rarer than californium and berkelium. “We can’t make enough einsteinium,” says Oak Ridge physicist James Roberto. Scientists need a new approach. They’ve switched to relatively untested techniques relying on different beams of particles.

    _____________________________________________________________
    Decay parade

    To discover oganesson-294 (with 294 protons and neutrons), scientists slammed calcium ions into a californium target and observed the chain of radioactive decays initiated by the new element.

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    _____________________________________________________________

    But any new approach would have to produce new elements often enough to be worthwhile. It took almost nine years for a Japanese experiment to prove the existence of nihonium. In that time, researchers spotted the element only three times.

    To avoid such long waits, scientists are carefully choosing their tactics and revving up improved machines to quicken the search.

    A team at the RIKEN Nishina Center for Accelerator-Based Science near Tokyo uses beams of vanadium (element 23), rather than calcium, slamming them into curium (element 96) in the quest to grab elemental glory and find element 119. The group is starting with an existing accelerator and will soon switch to an accelerator upgraded to pump out ion beams that pack more punch. That revamped accelerator could be ready within a year, says RIKEN nuclear chemist Hiromitsu Haba.

    Meanwhile, a new laboratory at the Joint Institute for Nuclear Research, or JINR, in Dubna called the Superheavy Element Factory boasts an accelerator that will crank out ion beams that pummel the target at 10 times the rate of its predecessor. In an upcoming experiment, scientists plan to crash beams of titanium (element 22) into berkelium and californium targets to attempt to produce elements 119 and 120.

    Once JINR’s new experiment is up and running, 119 might be discovered after a couple of years, says JINR nuclear physicist Yuri Oganessian, for whom oganesson, one of several elements discovered there, was named.

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    Scientists in Russia have built a new accelerator facility, the Superheavy Element Factory, to search for elements 119 and 120. JINR.

    Relativity rules

    Simply detecting an element, however, doesn’t mean scientists know much about it. “How would one kilogram of flerovium behave, if I had it?” Düllmann asks, referring to element 114. “It would be unlike any other material.”

    The known superheavy elements — those beyond number 103 on the table — are too short-lived to create a chunk big enough to hold in the palm of your hand. So scientists are limited to studying individual atoms, getting to know each new element by analyzing its properties, including how easily it reacts with other substances.

    One big question is whether the periodicity the table is named for applies to superheavy elements. In the table, elements are ordered according to their number of protons, arranged so that the elements in each column have similar properties. Lithium, sodium and others in the first column react violently with water, for example. Elements in the last column, known as noble gases, are famously inert (SN: 1/19/19, p. 18). But for the newest, heaviest elements at the periodic table’s outer reaches, that long-standing rule of chemistry may unravel; some superheavy elements may behave differently from neighbors sitting above them in the table.

    For nuclei crammed with 100-plus protons, a special type of physics takes center stage. Electrons zip around these giant nuclei, sometimes surpassing 80 percent the speed of light. According to Einstein’s special theory of relativity, when particles move that fast, they seem to gain mass. That property changes how closely the electrons hug the nucleus, and as a result, how easily the atoms share electrons to produce chemical reactions. In such atoms, “relativity rules, and standard common wisdom breaks down,” says nuclear physicist Witold Nazarewicz of Michigan State University in East Lansing. “We have to write new textbooks on those atoms.”

    _____________________________________________________________
    Getting heavy

    The nucleus of superheavy oganesson has 118 protons and many neutrons (blue and red). Its 118 electrons (green) surround the nucleus. Carbon, which is much lighter, contains just six protons and six electrons (not to scale).

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    T. Tibbitts
    _____________________________________________________________

    Some of the periodic table’s more familiar elements are already affected by special relativity. The theory explains why gold has a yellowish hue and why mercury is liquid at room temperature (SN: 2/18/17, p. 11). “Without relativity, a car would not start,” says theoretical chemist Pekka Pyykkö of the University of Helsinki. The reactions that power a car battery depend on special relativity.

    Relativity’s influence may surge as scientists progress along the periodic table. In 2018 in Physical Review Letters, Nazarewicz and colleagues reported that oganesson could be utterly bizarre (SN Online: 2/12/18). The table’s heaviest element, oganesson sits among the reclusive noble gases that shun reactions with other elements. But oganesson bucks the trend, theoretical calculations suggest, and may instead be reactive.

    Oganesson’s chemistry is a hot topic, but scientists haven’t yet been able to directly probe its properties with experiments because oganesson is too rare and fleeting. “All the theoreticians are now running around this element trying to make spectacular predictions,” says theoretical chemist Valeria Pershina of GSI. Similarly, some calculations suggest that flerovium might lean in the opposite direction, being relatively inert, even though it inhabits the same column as more reactive elements such as lead.

    Chemists are striving to test such calculations about how superheavy elements behave. But there is nothing traditional about these chemistry experiments. There are no scientists in white coats wielding flasks and Bunsen burners. “Because we make these things one atom at a time, we can’t do what most people think of as chemistry,” Lawrence Livermore’s Shaughnessy says.

    The experiments can run for months with only a few atoms to show for it. Scientists put those atoms in contact with other elements to see if the two react. At GSI, Düllmann and colleagues are looking at whether flerovium sticks to gold surfaces. Likewise, Shaughnessy and colleagues are testing whether flerovium will glom on to ring-shaped molecules, chosen so that the heavy element could fit inside the molecule’s ring. These studies will test how easily flerovium bonds with other elements, revealing whether it behaves as expected based on its place on the periodic table.

    It’s not just chemical reactions that can get wacky for superheavy elements. Atomic nuclei can be warped into various shapes when packed with protons. Oganesson may have a “bubble” in its nucleus, with fewer protons in its center than at its edges (SN: 11/26/16, p. 11). Still more extreme nuclei may be doughnut-shaped, Nazarewicz says.

    Even the most basic properties of these elements, such as their mass, need to be measured. While scientists had estimated the mass of the various isotopes of the latest new elements using indirect measurements, the arguments supporting those mass estimates weren’t airtight, says Jacklyn Gates of Lawrence Berkeley National Laboratory in California. “They hinge on physics not throwing you a curveball.”

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    Jacklyn Gates and Ken Gregorich of the FIONA experiment at Lawrence Berkeley National Laboratory made the first measurements of the masses of recently discovered elements 113 and 115.
    Marilyn Chung/Berkeley Lab

    So Gates and colleagues directly measured the masses of isotopes of nihonium and moscovium using an accelerator at Lawrence Berkeley. An apparatus called FIONA helped researchers measure the masses, thanks to electromagnetic fields that steered an ion of each element onto a detector. The location where each ion hit indicated how massive it was.

    The nihonium isotope the researchers detected had a mass number of 284, meaning its nucleus had a combined total of 284 protons and neutrons. Moscovium had a mass number of 288. Those masses were as predicted, the scientists reported in November in Physical Review Letters. It took about a month just to find one atom of each element.
    Island views

    If researchers could coax these fleeting elements to live longer, studying their properties might be easier. Scientists have caught enticing visions of increasing life spans lying just out of reach — the fabled island of stability (SN: 6/5/10, p. 26). Scientists hope that the isotopes on that island, which would be packed with lots of neutrons, may live long enough that their chemistry can be studied in detail.

    When the idea of an island of stability was proposed in the 1960s, scientists had suggested that the isotopes on its shores might live millions of years. Advances in theoretical physics have since knocked that time frame down, Nazarewicz says. Instead, nuclear physicists now expect the island’s inhabitants to stick around for minutes, hours or maybe even a day — a pleasant eternity for superheavy elements.

    To reach the island of stability, scientists must create new isotopes of known elements. Researchers already know which direction they need to row: They must cram more neutrons into the nuclei of the superheavy elements that have already been discovered. Currently, scientists can’t make atoms with enough neutrons to reach the island’s center, where isotopes are expected to be most stable. But the signs of this island’s existence are already clear. The half-lives of superheavy elements tend to shoot up as scientists pack more neutrons into each nucleus, approaching the island. Flerovium’s half-life increases by almost a factor of 700 as five more neutrons are added, from three milliseconds to two seconds.

    _____________________________________________________________
    Long life

    Each row below is an element, and each column a different isotope. Atoms are expected to be more stable on the island of stability (predicted location shown). As isotopes of elements (gray squares) approach the island, they tend to live longer, as more neutrons fill the nucleus. Flerovium’s half-life, for example, increases from 0.003 to two seconds.

    9
    T. Tibbitts

    Sources: S. Hofmann et al/Pure and Applied Chemistry 2018; W. Nazarewicz; Y. Oganessian
    _____________________________________________________________

    Reaching this island “is our big dream,” Haba says. “Unfortunately, we don’t have a very good method to reach the island.” That island is thought to be centered around isotopes that bulge with around 184 neutrons and something like 110 protons. Making such neutron-rich nuclei would demand new, difficult techniques, such as using beams of radioactive particles instead of stable ones. Although radioactive beams can be produced at RIKEN, Haba says, the beams aren’t intense enough to produce new elements at a reasonable rate.

    Still, superheavy element sleuths are keeping at it to learn how these weird atoms behave.

    End of the line

    To fully grasp nature’s extremes, scientists want to know where the periodic table ends.

    “Everybody knows at some point there will be an end,” Düllmann says. “There will be a heaviest element, ultimately.” The table will be finished when we’ve discovered all elements with isotopes that live at least a hundredth of a trillionth of a second. That’s the limit for what qualifies as an element, according to the standards set by the International Union of Pure and Applied Chemistry. More ephemeral nuclei wouldn’t have enough time to gather a crew of electrons. Since the give-and-take of electrons is the basis of chemical reactions, lone nuclei wouldn’t exhibit chemistry at all, and therefore don’t deserve a spot on the table.

    “Where it will exactly end is difficult to say,” Nazarewicz says. Calculations of how quickly a nucleus will decay by fission, or splitting in two, are uncertain, which makes it hard to estimate how long elements might live without actually creating them.

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    The linear accelerator at RIKEN in Japan, used to discover element 113*, is being refurbished to probe for element 119. RIKEN

    *According to a statement via email from LLNL, 113, was first found at LLNL; but on 113, Riken published first and so got the credit.

    And the final table may contain holes or other odd features. That could happen if, within a row of elements, there’s one spot for which no isotope persists long enough to qualify as an element.

    Another idiosyncrasy: Elements may not be arranged in sequential order by the number of protons they contain, according to calculations in a 2011 paper by Pyykkö in Physical Chemistry Chemical Physics. Element 139, for example, might sit to the right of element 164 — if such heavy elements indeed exist. That’s because special relativity alters the normal order in which electrons slot themselves into shells, arrangements that define how the electrons swirl about the atom. That pattern of shell filling is what gives the periodic table its shape, and the unusual filling may mean scientists decide to assign elements to spots out of order.

    But additions to the table could dry up before that happens if scientists reach the limit of their ability to create heavier elements. When elements live minuscule fractions of a second, even the atom’s trip to a detector may take too long; the element would decay before it ever had a chance to be spotted.

    In reality, there’s no clear idea of how to search for elements beyond 119 and 120. But the picture has seemed bleak before.

    “We should not underestimate the next generation. They may have smart ideas. They will have new technologies,” Düllmann says. “The next element is always the hardest. But it’s probably not the last one.”

    See the full article here .


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  • richardmitnick 8:39 am on October 24, 2017 Permalink | Reply
    Tags: , , , Periodic Table   

    From Manu Garcia: “Our atoms” 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    10/24/17
    Manu Astrologus

    Where do our atoms?
    1
    The hydrogen that is in your body, present in every molecule of water came from the Big Bang. No other significant sources of hydrogen in the universe. The carbon body formed by nuclear fusion within the stars, like oxygen. Much of the iron body formed during supernovae stars, stellar explosions that occurred long ago and far away. Gold in their jewelery was probably made of neutron stars during collisions that may have been visible as gamma-ray bursts short or events of gravitational waves. Elements such as phosphorus and copper are present in our bodies in small amounts but are essential for the functioning of all known life. It presented the periodic table is color-coded to indicate the best estimate of humanity in terms of nuclear origin of all known elements. Nuclear sites creating some elements, such as copper, are not well known and remain topics of observational and computational research.

    Image Credit & License: Wikipedia : Cmglee ; Data: Jennifer Johnson (OSU) .

    Posted in Astronomy Picture of the Day, APOD on 24 October 2017

    The periodic table.
    2
    Modern periodic table with 18 columns.

    Of Tximitx – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=52698867

    The periodic table is an arrangement of the chemical elements in a table, ordered by their atomic number (number of protons), its electron configuration and chemical properties. This arrangement shows periodic trends, as elements with similar behavior in the same column.

    In the words of Theodor Benfey, table and periodic law “are the heart of chemistry, comparable to the theory of evolution in biology (which happened to the concept of the Great Chain of Being), and the laws of thermodynamics in classical physics. ”

    The rows of the table are called periods and columns groups. Some groups have names. For example group 17 is the halogens and the group 18 of the noble gases. The table also is divided into four blocks with some similar chemical properties. Because the positions are ordered, the table can be used to obtain relationships between the properties of the elements, or predict properties of new elements yet discovered or synthesized. The periodic table provides a useful tool for analyzing the chemical behavior and is widely used in chemistry and other science framework.

    Dmitri Mendeléyev in 1869 published the first version of the periodic table was widely recognized. The developed to illustrate periodic trends in the properties of the then known elements, to sort the items based on its chemical properties, although Julius Lothar Meyer, working separately conducted an order from the physical properties of atoms . Mendeleev also predicted some properties of then unknown elements anticipated that occupy the empty places in your table. Subsequently it showed that most of his predictions were correct when the items in question were discovered.

    Mendeleev periodic table has since been expanded and enhanced with the discovery or synthesis of new elements and development of new theoretical models to explain the chemical behavior. The current structure was designed by Alfred Werner from the version of Mendeleev. There are also other newspapers arrangements according to different properties and use it as you want to give (didactics, geology, etc.).

    Have been discovered or synthesized all elements of atomic number 1 (hydrogen) to 118 (oganesón); IUPAC confirmed the elements 113, 115, 117 and 118 on December 30, 2015, and their names and official symbols were made public on November 28, 2016. The first 94 exist naturally, although some only found in small amounts and were synthesized in the laboratory before being found in nature. the elements with atomic numbers 95 to 118 only they have been synthesized in laboratories. There were also produced numerous synthetic radioisotopes of elements present in nature. Elements of 95-100 existed in nature in the past but is currently not. The research to find new elements for synthesis of higher atomic numbers continues.

    See the full article here .

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  • richardmitnick 9:13 am on October 28, 2015 Permalink | Reply
    Tags: , Isotopes, , Nuclides, Periodic Table   

    From LLNL: “Lab scientists discover five new nuclei” 


    Lawrence Livermore National Laboratory

    Oct. 27, 2015

    Anne M Stark
    stark8@llnl.gov
    925-422-9799

    1
    Lawrence Livermore National Laboratory scientists were part of an international team that discovered five new nuclei: U 218, Np 219, Bk 233, Am 223 and Am 229.

    Lawrence Livermore scientists, in conjunction with international researchers, have discovered five new atomic nuclei to be added the chart of nuclides.

    The study, conducted this fall, focuses on developing new methods of synthesis for super heavy elements. The newly discovered, exotic nuclei are one isotope each of heavy elements berkelium, neptunium and uranium and two isotopes of the element americium.

    Other participants include scientists from Manipal University, India; GSI-Giessen, Germany; Justus Liebig University Giessen, Germany; Japan Atomic Energy Agency; and the joint Institute for Nuclear Research in Russia. The results are published in the journal Physics Letters B . The Lab’s Dawn Shaughnessy, Ken Moody, Roger Henderson and Mark Stoyer participated in the experiments.

    Every chemical element comes in the form of different isotopes. These isotopes are distinguished from one another by the number of neutrons in the nucleus, and thus by their mass. The newly discovered isotopes have fewer neutrons and are lighter than the previously known isotopes of the respective elements.

    To date, the known Periodic Table comprises more than 3,000 isotopes of 114 confirmed chemical elements.

    Periodic Table 2014
    Periodic Table of elements, 2014, NIST

    According to scientific estimates, more than 4,000 additional, undiscovered isotopes also should exist. Due to their low number of neutrons, their structure is very exotic and therefore interesting for the development of theoretical models describing atomic nuclei.

    “These results really push what we know about nuclear structure to the extreme, neutron-deficient end of the chart of the nuclides,” Shaughnessy said. “When you realize that naturally occurring uranium has 146 neutrons and this new isotope only has 124 neutrons, it shows how much more we still have yet to learn about nuclear structure and the forces that hold the nucleus together.”

    Scientists at LLNL have been involved in heavy element research since the Laboratory’s inception in 1952 and have been collaborators in the discovery of six elements — 113, 114 (Flerovium), 115, 116 (Livermorium), 117 and 118.

    Apart from discoveries themselves, the discovery is the first proof of the new technique for production of these exotic nuclides.

    For the experiment, the scientists shot at a 300-nanometer-thick foil of curium with accelerated calcium nuclei. In the collisions studied, the atomic nuclei of the two elements touched and formed a compound system for an extremely short time.

    Before the compound system could break apart again, after about a sextillionth of a second, the two nuclei involved exchanged a number of their nuclear building-blocks — protons and neutrons. Different isotopes formed as the end products of this exchange.

    The isotopes of berkelium, neptunium, uranium and americium discovered were created as the end products of such collisions. They are unstable and decay after a few milliseconds or seconds, depending on the isotope. All of the resulting decay products can be separated and analyzed using special filters composed of electrical and magnetic fields. The scientists used all of the decay products detected to identify the new isotope that has been created.

    The current experiments will make it possible to explore previously unknown areas on the isotope chart. The elements 107 to 112 were discovered using the same experimental facility at GSI.

    See the full article here .

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