Tip: Full-time general high school textbook (trial revision, compulsory) - Chemistry Book 1 - Elemental Cycle Law (P96)
The search for “ transuranic elements†actually started as early as 1934. This year, Fermi discovered in Italy that when he bombards an element with a newly discovered subatomic particle called a neutron, it often turns the bombarded element into an atomic number greater than it. element. In this case, is it possible to turn uranium into element 93—a man-made element that does not exist in nature? Fermi’s group then used neutrons to bombard uranium, and they obtained a product that they thought The product they obtained is undoubtedly the No. 93 element and is called "Uranium X".
In 1938, Fermi won the Nobel Prize in Physics for his research on neutron bombardment. The true meaning of his discovery, or the consequences of this discovery on humans, were not even thought of at the time. Just like another Italian, Columbus, what he found was not what he was looking for, but the importance was far more than he could have imagined at the time.
It’s enough to point out a point here: after people followed a series of false signs and made a series of recourses, they finally discovered that the experiment Fermi did not actually “made†a new element, but Split the uranium atom into roughly equal halves. But when some physicists began to study this process in 1940, element 93 suddenly appeared like an accidental harvest of their experiments.
Among the many elements that appear when bombarding uranium with neutrons, there is an element that was initially unrecognizable. This made Macmillan of the University of California begin to realize that the neutrons released in fission are likely to have turned some uranium atoms into higher atomic elements, as well as what Fermi had hoped to happen. Lun and physical chemist Abelson can prove that the unidentified element is actually the 93rd element. The evidence confirming the existence of this element is its radiological characteristics, which is a common feature of all the newly discovered elements.
Macmillan believes that there is probably another type of transuranic element mixed with element 93. Later, the chemist Siboge and his collaborators, Wall and Kennedy, quickly confirmed that this was the case, and pointed out that this element is the 94th element.
Elements 93 and 94 are named 镎 and 分别, respectively. It was later discovered that they also existed in nature because people later discovered trace amounts of strontium and barium in uranium ore. In this way, the element of uranium is no longer the heaviest natural element.
Later, Xiboge and a research team at the University of California continued to receive one more transuranic element. In 1944, they obtained elements 95 and 96 by bombarding the scorpion with subatomic particles, and named them 镅 and 分别, respectively, which were named to commemorate the Curies.
After they produced a sufficient number of singularities, they bombarded these elements and succeeded in obtaining elements 97 and 98 in 1949 and 1950. They named these two elements as 锫 and 锎. In 1951, Siberg and Macmillan won the Nobel Prize in Chemistry for this series of achievements.
Elements 99 and 100 were discovered on a more dramatic occasion, when the first hydrogen bomb exploded in the Pacific Ocean in November 1952. Although their existence was detected early in the explosive debris, it was not until the University of California research team obtained a small amount of these two elements in the laboratory in 1955 that they were identified and named as 锿 and 镄, respectively. The former is to commemorate Einstein, the latter is to commemorate Fermi, because both of them died in the past few months. Later, the research team bombarded a small amount of cockroaches and obtained the No. 101 element. They named this element 钔 to commemorate Mendeleev.
Then, the University of California, in cooperation with the Nobel Institute in Sweden, took a step forward on this basis. The Nobel Institute carried out a particularly complex bombardment that produced a small amount of element No. 102, which was named 锘, named after the Nobel Institute, but the experiment was not confirmed. Later, someone used other methods instead of the one first introduced by the Nobel Institute to obtain this element. Therefore, there was a delay after the name was officially recognized as the element.
In 1961, a research team at the University of California detected some of the atoms of element 103 and named it "铹" in honor of Lawrence because he died not long ago. Later, the research team led by the Soviet Union Fryrov reported that they obtained elements 104 and 105 respectively in 1964 and 1967, but the methods they used to produce these two elements were not confirmed. Later, the research team led by Giuso in the United States produced these two elements in other ways.
Thus, there was a fierce debate over who first discovered the two elements, and both research groups claimed that they had the right to name the two elements. The International Union of Pure and Applied Chemistry has solved the naming disputes. Since 1971, it has met many times and has not been resolved. To this end, the Union's Inorganic Chemistry Group officially announced in August 1977 the proposal to name elements above 100 in a mixture of Latin and Greek numbers. Accordingly, the English name of the 104 element is unnilquadium, the symbol Unq; the English name of the 105 element is the unnilpentium symbol Unp.
However, the competition is not over. In 1974, Fryov's research team bombarded the lead target with an accelerator-accelerated chromium ion, and synthesized the isotope of element No. 106 with a mass of 259. Almost at the same time, Giosso in the United States bombarded 259 micrograms of ruthenium target with an oxygen ion accelerated by an accelerator, and synthesized an isotope of element No. 106 with a mass of 263, and identified it by measuring the 263 decay chain.
1976 Eph Liao Luofu research team used an accelerator to accelerate the chromium ions bombarding bismuth target, the synthesis of the mass number 107 element 261 isotope, and identified by the method of decay chain body measuring 261, this time the Soviets ahead . Later, in 1981, Alumberg and others of the Darmstadt Heavy Ion Institute in the Federal Republic of Germany bombarded the target with accelerated chromium ions and synthesized the isotope of 107 elements with a mass of 262. During the experiment, they were able to obtain 2 alpha particles from 262 decay per day, and a total of 6 counts were observed.
In 1982, Alumberg's scientific team bombarded the target with iron ions accelerated by an accelerator, and synthesized the isotope of element No. 109 with a mass of 266. In a one-week bombardment synthesis experiment, only one new elemental atom was obtained; alpha particles with an energy of 11.10 MeV were emitted at 5 seconds after 266 synthesis. They used this unique event to successfully identify them in four different ways, especially by measuring the 266 decay chain body to confirm the synthesis of element 109.
The discovery of element 108 was later than element 109. In 1984, Alum Berger again bombarded the lead target with an iron ion accelerated by an accelerator, and synthesized an isotope (or 266) of element 108 of mass 265. A total of three 265 (or 266) atoms were recorded with lifetime measurements of 24, 22, and 34 milliseconds, and the synthesis of element 108 was confirmed by measuring the decay chain of 265. Since then, no new elements have been discovered or synthesized.
When climbing the ladder of transuranic elements, each level is more difficult before the first level. The larger the atomic number, the more difficult it is to collect and the more unstable it is. When the level of é’” is reached, the identification of it has begun with only seventeen atoms. Fortunately, radiation detection technology has been very high since 1955. Scientists at the University of Berkeley installed an alarm bell on their instruments. Each time a cesium atom is generated, the identifiable radiation emitted during its decay causes the bell to ring loudly to announce that it has occurred. Such a thing.
From Mendeleev officially proposed the elemental cycle law, to the time of the synthesis of element 108 in 1984, people discovered or synthesized 46 elements, the discovery of each element proved Mendeleev's The correctness of the theory. Moreover, it motivates people to study the deeper theoretical basis of the periodicity of elements, thus guiding people into the world of atoms.Hemp Flour
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