Einsteinium radioactivity

Each of the elements has a number of isotopes (2,4), all radioactive and some of which can be obtained in isotopicaHy pure form. More than 200 in number and mosdy synthetic in origin, they are produced by neutron or charged-particle induced transmutations (2,4). The known radioactive isotopes are distributed among the 15 elements approximately as follows actinium and thorium, 25 each protactinium, 20 uranium, neptunium, plutonium, americium, curium, californium, einsteinium, and fermium, 15 each herkelium, mendelevium, nobehum, and lawrencium, 10 each. There is frequently a need for values to be assigned for the atomic weights of the actinide elements. Any precise experimental work would require a value for the isotope or isotopic mixture being used, but where there is a purely formal demand for atomic weights, mass numbers that are chosen on the basis of half-life and availabiUty have customarily been used. A Hst of these is provided in Table 1. 

Radioactive, short-lived element. The longest-lived isotope (256Md) has a half-life of 55 days. To date, only a few atoms have been prepared by a nuclear reaction between einsteinium and helium nuclei in a particle accelerator. 

These elements have all been named for famous scientists or for the places of their creation. For example, americium, berkelium, and californium were named after obvious geographical locations. Nobelium was named for the Nobel Institute, although later study proved it was not really created there. Curium was named for Marie Curie, the discoverer of radium. Einsteinium was named for the famous physicist, Albert Einstein. Fermium and lawrencium were named for Enrico Fermi and Ernest O. Lawrence, who made important discoveries in the field of radioactivity. Mendelevium was named for the discoverer of the periodic chart. 

ISOTOPES There are total of 20 isotopes of einsteinium. Einsteinium is not found in nature. All the isotopes are radioactive and are produced artificially. Their half-lives range from eight seconds to 472 days. None have exceptionally long half-lives. 

Einsteinium does not exist in nature and is not found in the Earth s crust. It is produced in small amounts by artificial nuclear transmutations of other radioactive elements rather than by additional explosions of thermonuclear weapons. The formation of einsteinium from decay processes of other radioactive elements starts with plutonium and proceeds in five steps as follows ... 

The radioisotopes of einsteinium are highly unstable and radioactive. The small amount of the element and its compounds produced are not likely to be available in most laboratories. Thus, they do not pose any general hazard except in the case of scientists working with nuclear materials who must take precautions in handling exotic elements. 

Einsteinium isotopes are separated on an ion exchange column and eluted with a solution of ammonium citrate. Radioactive isotopes are identified by an activity detector. 

Radioactivity (continued) compounds in atmosphere, 3 287-288 einsteinium, 31 34 neptunium, 31 21 plutonium, 31 23-24 thorium, 31 17 uranium, 31 19 Radiocarbon, 3 301-317 artificial, 3 327 atmospheric, 3 328 nuclear testing and, 3 312-314 constancy in atmosphere, 3 309 dating, fundamental assumptions of, 3 308-309... 

But for chemists, the hydrogen bomb tests had a happier fallout too. Scientists at the Mike test collected coral from a nearby atoll contaminated with radioactive debris, and sent it to Berkeley for analysis. There the nuclear chemists found two new elements, with atomic numbers 99 and 100. They were named after two of the century s most creative physicists einsteinium and fermium. 

EINSTENIUM. CAS 7429-92-71. Chemical element symbol Es, at. no. 99. at. wt. 254 (mass number of the most stable isotope), radioactive metal of the Actinide series, also one of the Transuranium elements. Both einsteinium and fermium were formed tit a thermonuclear explosion that occurred in the South Pacific in 1952. The elements were identified by scientists from the University of California s Radiation Laboratory- the Argonnc National Laboratory, and the I. os Alamos Scientific Laboratory. It was observed that very heavy uranium isotopes which resulted from the action of the instantaneous neutron dux on uranium (contained in the explosive device) decayed to form Es and Fm. The probable electronic configuration of Es is... 

All known isotopes of einsteinium are radioactive. The first evidence of lltcir existence was obtained by ion-exchange methods applied lo coral rocks obtained from Eniwetok Atoll alter (he thermonuclear explosion. The first pure isotope found was 3,3Es produced by prolonged treatment of plutonium-239 with neutrons in the Area. Idaho. Testing Reactur. The most stable is JMEs. half-life 270 days, and therefore the mass number 254 is carried in the atomic weight tabic. Others include - Es- Es. 48Es- Es, and s Es. Es. 

The nuclear area is one that has been heavily dependent upon isotope ratio mass spectrometry performed by thermal ionization. Applications in this area are among the major reasons for the continued push to analyze smaller and smaller samples. There are two primary reasons for this (1) maximum practicable reduction of the hazards associated with radioactivity and (2) presence of often only a very small amount of the target element available. Areas addressed include evaluation of uranium enrichment processes [86], isotopic analysis of transuranium elements (all elements through einsteinium have been analyzed) [87], and environmental monitoring for release of uranium and other actinides [88,89]. This last area has received renewed emphasis in the wake of the Gulf War [90]. 

Einsteinium (Z = 99) and fermium (Z = 100) were identified in 1952 and 1953, respectively, by Ghiorso and others in the radioactive debris of the first thermonuclear explosion. Hints of the formation of these elements were found in dust samples from the remotely controlled aircrafts used in this test. Then, the elements were isolated by processing larger amounts of the radioactive coral material from the test site and named in honour of Einstein and Feimi. The elements had been formed by multineutron capture,... 

All 19 isotopes of einsteinium are radioactive. The most stable is einsteinium-254. Its half life is 275.7 days. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element s name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element... 

The half life of a radioactive element is the time it takes for half of a sample of the element to break down. For example, suppose that scientists made 10 grams of einsteinium-254. About eight months later (275.7 days later), only 5 grams of the element would be left. After another eight months (275.7 days more), only half of that amount (2.5 grams) would remain. 

Scientists know too little about einsteinium to be aware of its health effects. As a radioactive element, however, it does pose a threat to human health. 

Seaborg, Glen T. (1912-1999). An American chemist who won the Nobel Prize for chemistry in 1951 along with McMillan. He did research in nuclear chemistry, physics, and artificial radioactivity. He discovered the elements plutonium, americum, berkelium, californium, einsteinium, fermium, and medelevium with his colleague. He codiscovered numerous isotopes and radioisotopes. His Ph.D. is from the University of California at Berkeley. 

The purpose of all this equipment is to isolate tiny quantities of the rare synthetic elements like americium, berke-lium, and einsteinium. They are present in the irradiated plutonium napkin rings along with the great quantity of highly radioactive fission products. 

The microscope spectrophotometer system in routine use at the TRL is described in reference (7), so no details of the apparatus and its use are given here. Instead a brief description of the reason for developing and continually refining the microscope spectrophotometer facility will be presented. Historically the way to characterize a solid-state sample of a transplutonium element has been by standard X-ray powder diffraction analysis. When a systematic study of element 99, einsteinium, was undertaken, it was found that obtaining useful diffraction data from Es-containing materials was a very difficult, if not an impossible, task (22). The intensely radioactive Es-253 not only caused rapid blackening of the film used to record the diffraction pattern, but more importantly, it degraded the crystallinity of the sample. 

Mendelevium was discovered in 1955 by Albert Ghiorso, Bernard G. Harvey, Gregory R. Choppin, Stanley G. Thompson, and Glenn T. Seaborg via the bombardments of a minute quantity of a rare, radioactive isotope of einsteinium ( Es) with a-particles in the 60-inch cyclotron of the University of California, Berkeley, which produced Md. Only 17 atoms were detected. Md is the first element to be produced and chemically identified on a one-atom-at-a-time basis. Mendelevium-256 decayed by electron capture (with a 1.3-hour half-life) to the known daughter nuclide fermium-256 ( Tm), which decayed primarily by spontaneous fission (with a half-life of... 

After the discovery of uranium radioactivity by Henri Becquerel in 1896, uranium ores were used primarily as a source of radioactive decay products such as Ra. With the discovery of nuclear fission by Otto Hahn and Fritz Strassman in 1938, uranium became extremely important as a source of nuclear energy. Hahn and Strassman made the experimental discovery Lise Meitner and Otto Frisch provided the theoretical explanation. Enrichment of the spontaneous fissioning isotope U in uranium targets led to the development of the atomic bomb, and subsequently to the production of nuclear-generated electrical power. There are considerable amounts of uranium in nuclear waste throughout the world, see also Actinium Berkelium Einsteinium Fermium Lawrencium Mendelevium Neptunium Nobelium Plutonium Protactinium Rutherfordium Thorium. 

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