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New Elements - Kartoffelsalat - 02-03-2004
Quote:Uut and Uup Add Their Atomic Mass to Periodic Table
By JAMES GLANZ
A team of Russian and American scientists are reporting today that they have created two new chemical elements, called superheavies because of their enormous atomic mass. The discoveries fill a gap at the furthest edge of the periodic table and hint strongly at a weird landscape of undiscovered elements beyond.
The team, made up of scientists from Lawrence Livermore National Laboratory in California and the Joint Institute for Nuclear Research in Dubna, Russia, is disclosing its findings in a paper being published today in Physical Review C, a leading chemistry journal. The paper was reviewed by scientific peers outside the research group before publication.
"Two new elements have been produced," said Dr. Walt Loveland, a nuclear chemist at Oregon State University who is familiar with the research. "It's just incredibly exciting. It seems to open up the possibility of synthesizing more elements beyond this."
The periodic table is the oddly shaped checkerboard â with an H for hydrogen, the lightest element, in the upper-left-hand corner â that hangs in chemistry classrooms the world over. Each element has a different number of protons, particles with a positive electrical charge, in the dense central kernel called the nucleus.
The number of protons, beginning with one for hydrogen, fixes an element's place in the periodic table and does much to determine an element's chemical properties: ductile and metallic at room temperature for gold (No. 79), gaseous and largely inert for neon (10), liquid and toxic for mercury (80).
Elements as heavy as uranium, No. 92 on the list, are found in nature, and others have been created artificially. But much heavier elements have been difficult to make, partly because they became increasingly unstable and short-lived.
Still, for roughly half a century, nuclear scientists have been searching for an elusive "island of stability," somewhere among the superheavies, in which long-lived elements with new chemical properties might exist. Dr. Loveland said that the new results indicated that scientists might be closing in on that island.
"We're sort of in the shoals of the island of stability," said Dr. Kenton J. Moody, a Livermore nuclear physicist who was one of the experimenters in the work.
"It's an amazing effect," he added. "We're really just chipping away at the edges of it."
The experiments took place at a cyclotron, a circular particle accelerator, in Dubna, where the scientists fired a rare isotope of calcium at americium, an element used in applications as varied as nuclear weapons research and household smoke detectors. Four times during a month of 24-hour-a-day bombardment in July and August, scientists on the experiment said, a calcium nucleus fused with an americium nucleus and created a new element.
Each calcium nucleus contains 20 protons and americium 95. Since the number of protons determines where an element goes in the periodic table, simple addition shows the new element to bear the atomic number 115, which had never been seen before. Within a fraction of a second, the four atoms of Element 115 decayed radioactively to an element with 113 protons. That element had never been seen, either. The atoms of 113 lasted for as long as 1.2 seconds before decaying radioactively to known elements.
Scientists generally do not give permanent names to elements and write them into textbooks until the discoveries have been confirmed by another laboratory. By an international convention based on the numbers, element 113 will be given the temporary name Ununtrium (abbreviated Uut for the periodic table) and element 115 will be designated Ununpentium (Uup).
Dr. Loveland said he agreed that the new elements would require independent confirmation before they could receive final acceptance. And he conceded that the Dubna find was likely to receive more than the usual amount of scrutiny: two years ago, the reported discovery of Element 118 was retracted after a scientist at Lawrence Berkeley National Laboratory was found to have fabricated evidence.
I heard about this today form my chem teacher. Obviously they aren't too useful, lasting only a couple of seconds, but it's pretty impressive nonetheless.
Here's the link: http://www.nytimes.com/2004/02/01/science/01ELEM.html
New Elements - Jeunemaitre - 02-03-2004
If you're interested in collision experiments, you might also look at the work being done at Brookhaven National Labs using the Relativistic Heavy Ion Collider (The RHIC).
Using the nuclei of gold atoms that have been accelerated to 99.995% the speed of light (source: FAQ). The research predominantly seeks to recreate the state of matter just preceding the formation of "larger subatomic particles" that existed about 10^-4 seconds before the big bang (at a temperature of more than 10^12 k).
There's a series of descriptions of some of the experimental apparatus used at the ring, and they have some pretty interesting graphic illustrations the effects of a collision.
edit: correcting subject agreement
New Elements - Lady Vashj - 02-04-2004
What I want to see are neon and helium compounds. Those might have some practical value.
Question? What sort of matter do they theorize existed before the big bang?
New Elements - Jeunemaitre - 02-04-2004
Lady Vashj,Feb 4 2004, 07:47 AM Wrote:Question? What sort of matter do they theorize existed before the big bang?
DISCLAIMER: I am not a nuclear physicist, nor do I play one on TV, nor did I stay at a Holiday Inn Express last night, but I did find out the following information from the RHIC website: Main site or the collision primer series of pages starting here
The theory goes: as you raise the temperature of any substance, you increase the level of molecular motion in that substance (definition of temperature). If you raise the temperature high enough, the electrons will begin to disassociate from the nuclei, leaving a plasma state of positive ions floating through a sea of randomly distributed electrons. (This is how that come up with the "heavy ions" that are used in the RHIC)
Now that you have naked nuclei, if you continue to increase the temperature, you can reach a plasma state where the protons start to pull away from the neutrons, reversing nucleosynthesis (this is thought to happen just above 10^9th k). Keep raising the temperature to up above 10^12 k and you begin to reverse a process called hadronization. Hadrons are the commonly known nucleic subatomic particles (I think this refers to protons and neutrons only), and they are made up of smaller particles called quarks. There are several flavors of quarks (top, left, etc.), a specific combination of which creates a proton, and a different combination creates a neutron. The quarks are held together by bridge particles called gluons (glue - ons, physicists can be really uncreative sometimes). When you get to the point of reversing hadronization, you break the bigger particles into the quarks and gluons that make them up forming a "quark-gluon" plasma.
It's thought that this quark-gluon plasma existed as the only state of matter immediately preceding the big bang. Because there's no practical way to keep a bunch atoms at a temperature that high for any length of time in order to study them, physicists have to do it another way. Enter colliders: by accelerating atoms to very high speeds and smashing them together to see what flies out of the collision. With enough data about what comes out of the collision and what went into it, they can infer what happened in the instant when the two nuclei collided.
edit: stupid fingers, wrong button. Never hit submit post before typing the post
New Elements - Lady Vashj - 02-04-2004
Interesting theory. I suppose it's much more feasible than anything else anyone has come up with so far.
The six known flavors of quark are up, down, top, bottom, charm, and strange. Protons are two up and one down, neutrons are one up and two down. The other four don't seem to form anything stable.
New Elements - Cryptic - 02-04-2004
Quote:By an international convention based on the numbers, element 113 will be given the temporary name Ununtrium (abbreviated Uut for the periodic table) and element 115 will be designated Ununpentium (Uup).
So when are they going to find Unobtainium?
:P
New Elements - Raziel - 02-04-2004
^ Some time past 120 protons, I think, which should be the next stable "plateau".
That's if I have my grade 12 physics memories straight.
I believe that theoretically there should be a whole bunch of high-proton stable elements up there waiting to be "discovered".
New Elements - Dozer - 02-05-2004
Quote:that existed about 10^-4 seconds before the big bang (at a temperature of more than 10^12 k).
:blink: :blink: :blink: :blink: :blink: :blink: :blink: :blink:
That's just mind-boggling.
New Elements - Occhidiangela - 02-08-2004
Quote:that existed about 10^-4 seconds before the big bang (at a temperature of more than 10^12 k).
Not quite enough time for a cigarette after that big bang. :D
New Elements - TheDragoon - 02-08-2004
And then you can put the ideas of Hyperspace and String Theory in there and say that at the big bang that a bunch of "curled up" dimensions of today were completely uncurled and everything existed in many more dimensions than we normally see today. With those extra dimensions, I wonder if some of the unstable things of today were more stable. :)