AMERICIUM

ămərĭˈshēəm, artificially produced radioactive chemical element; symbol Am; at. no. 95; mass no. of most stable isotope 243; m.p. about 1,175 degrees Celsius; b.p. about 2,600 degrees Celsius; sp. gr. 13.67 at 20 degrees Celsius; valence +2, +3, +4, +5, or +6. Americium is a silver-white metal thought to have either a loose-packed cubic or a close-packed double hexagonal crystalline structure. The pure metal has been prepared by reduction of americium trifluoride with barium vapor at about 1,100 degrees Celsius. It tarnishes slowly in dry air. All 16 known isotopes are radioactive. Americium-243, the most stable isotope, has a half-life of over 7,300 years. Americium-241, which has a half-life of about 430 years, is more often used in chemical investigations, since it is easily prepared in a fairly pure form; it is also used in industrial measuring devices, radiology, and household smoke detectors. The fourth transuranium elementto be synthesized, Americium is a member of the actinide series in group IIIb of the periodic table. It was discovered in 1944 by Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, and Albert Ghiorso, who bombarded plutonium-239 with neutrons to form plutonium-241, which decays to form americium-241.

____________________

The Columbia Encyclopedia, Sixth Edition Copyright© 2004, Columbia University Press. Licensed from Lernout & Hauspie Speech Products N.V. All rights reserved.

-1727-

Search the Library
Books
Journals
Magazines
Newspapers
Encyclopedia
Advanced Search
About Questia
Questia is the world's largest online academic library offering full-text books, journals, and articles on thousands of topics.

Join Now...
Questia Books and Articles on: Americium
We found: 129 results
By media type:
 

Books:

 

60  

 

Journal articles:

 

17  

 

Magazine articles:

 

28  

 

Newspaper articles:

 

11  

 

Encyclopedia articles:

 

13  

 

books on: Americium  - 60 results

       More book Results: 1-10 11-20 21-30 31-40 41-50 >>  
 
...radiation poisoning leading to death. * * * AMERICIUM Transuranic Elements SYMBOL: Am ATOMIC...ISOTOPES: The most important isotope is americium-241, an alpha emitter, with a half...other radioactive isotopes ranging from americium-232 to americium-247, with half...
...the alpha-emitting isotope of americium, Am 241 , with a half life of...prominent role in the elucidation of americium chemistry. Early work employing...technique led to the conclusion that americium existed in aqueous solution only...
...However, in this system, there is sufficient americium-243 first to dominate after americium-241 has mostly decayed away, and later...of plutonium-239 see the decay chain of americium-243 through neptunium-239 to plutonium...
...plutonium are summarized in Table 8.1 . 8.2.3 Americium Atomic Number 95 . Americium, the element with atomic number 95, was the...life of 470 years. This element was named americium , symbol Am after the Americas , by analogy to...
...at Taranaki was set at about 40 kBq of americium-241/square metre, with further allowance...criterion at Taranaki was three kBq of americium-241/square metre averaged over one...the differing ratios of plutonium to americium. Since this criterion would have required...
More book Results: 1-10 11-20 21-30 31-40 41-50 >>

 

journal articles on: Americium  - 17 results

       More journal Results: 1-10 11-17 >>  
 
...minor actinides, e.g., plutonium, americium, curium or neptunium from the spent...Neptunium (Np), long-term radio- <br/ Americium (Am) and toxicity of the <br/ Curium...Neptunium (Np), combination with Pu <br/ Americium (Am) and in fast reactors. <br...
...claim arising from the insureds disposal of radioactive americium-241 into a municipal sewer system. The NRC regulates americium241...opinion was based on the courts finding that the release of americium-241 was intentional and, therefore, barred under the qualified...
...unwanted radioactive materials could contain isotopes such as Americium-241, Plutonium-238 and 239, and Curium-244.8 Figure...accountability over them? Remember, a machine containing Americium-241 sealed sources may be obsolete and fully depreciated...
...nuclear power plant revealed elevated levels of plutonium and americium (Schmitz-Feuerhake et al. 2003); and some but not all...environmental contaminations by uranium, thorium, plutonium, and americium isotopes indicate an accidental release of radioactivity as...
...characteristics of nuclear, chemical, biological, and radiological weapons technology. For example, the reader learns that Americium-241 is a radioactive element and an alpha ray emitter with a half-life of 432.7 years. Depending on ones professional...
More journal Results: 1-10 11-17 >>

 

magazine articles on: Americium  - 28 results

       More magazine Results: 1-10 11-20 21-28 >>  
 
...extremely long-lived transuranic alpha-emitters plutonium, americium, and neptunium. South Korea plans to irradiate these latter...plutonium mixed with other transuranic elements, such as americium and neptunium. The United States and South Korea recently...
...a process called ionization; these detectors contain a small piece of an element called americium, which gives off low-level radiation. The americium sets up a current within the detector; in the presence of smoke, the current is disrupted...
...port. I went to the body counter and came up positive in americium, a deadly daughter-product of plutonium. It was written...someone poked a hole in my glovebox glove. Plutonium and americium-contaminated ash from a 1969 fire at Rocky Flats puffed...
...notably cerium-144), and the other transuranic elements: americium, curium, and neptunium. This is the basis for the claim...in a spent fuel assembly. Keeping the transuranic elements americium and curium mixed with plutonium in pyroprocessing would increase...
...radioactive isotopes of the transuranic elements neptunium, americium, and curium. These materials, formed during irradiation...is the actinides (specifically, isotopes of plutonium, americium, and curium) that will contribute most to radioactive decay...
More magazine Results: 1-10 11-20 21-28 >>

 

newspaper articles on: Americium  - 11 results

       More newspaper Results: 1-10 11-11 >>  
 
...in a Welsh university and found to contain alarming levels of dangerous radioactive agents including americium, caesium and cobalt. Americium is one of the most toxic substances known to man and is described by experts as being as deadly as plutonium...
...highly dangerous quantities of radioactive caesium 137 and americium-beryllium. The soil testers had been sent to Iran by a...devices to harvest sufficient material for a dirty bomb. Americium-beryllium is an extremely effective element for the construction...
...several unoccupied cabins in order to secure the tiny amounts of americium-Its rare for boy scouts to be radioactive - their merit...several unoccupied cabins in order to secure the tiny amounts of americium-241 they contain. Trying to obtain radium, he bought old...
...nuclear campaigners blame these high levels on traces of plutonium (as well as other dangerous elements such as caesium and americium, which are used in the production of nuclear fuel) in the mud. This is because waste water from Sellafield has been discharged...
...Sioux and Cheyenne c) Shawnee and Lakota d) Mohawk and Seneca 5. What are Atimony, Holmium, Ytterbium, Bismuth and Americium? a) moons of Jupiter b) nuclear fuels c) elements d) subatomic particles 6. In Christian art, what does the depiction...
More newspaper Results: 1-10 11-11 >>

 

encyclopedia articles on: Americium  - 13 results

       More encyclopedia Results: 1-10 11-13 >>  
 
AMERICIUM am ri she m, artificially produced radioactive...valence +2, +3, +4, +5, or +6. Americium is a silver-white metal thought to...metal has been prepared by reduction of americium trifluoride with barium vapor at about...
PERIODIC TABLE OF THE ELEMENTS: AMERICIUM Periodic Table of the Elements: Americium Atomic Number: 95 Atomic Symbol: Am Americium Atomic Weight: (243) Electron Configuration: 2 8 18 32 25 8 2 ____________________ Copyright...
...half-lives of 0.1 sec and 3 sec, respectively, by bombarding americium-243 atoms with neon-22 ions. In 1970 the same team announced that by using the same americium and neon isotopes but a different detection technique they had created...
...Atomic Energy Commission from 1961 to 1971. Seaborg codiscovered the elements plutonium (and its isotope Pu-239), americium , curium , berkelium , californium , einsteinium , fermium , mendelevium , and nobelium . For discoveries concerning the chemistry...
ELEMENTS (table) Elements actinium Ac 89 227.0278 1050. 3200. 300 aluminum Al 13 26.98154 660.37 2467. americium Am 95 (243) 1172. 2600. antimony Sb 51 121.75 630.74 1750. argon Ar 18 39.948 189.2 185.7 arsenic As 33 74...
More encyclopedia Results: 1-10 11-13 >>

 About Questia   ::   Privacy   ::   Contact