95 plutonium ← americium → curium Eu ↑ Am ↓ (Uqp) Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	americium, Am, 95
Chemical series	actinides
Group, Period, Block	n/a, 7, f
Appearance	silvery white sometimes yellow
Standard atomic weight	(243)  g·mol−1
Electron configuration	[Rn] 5f7 7s2
Electrons per shell	2, 8, 18, 32, 25, 8, 2
Physical properties
Phase	solid
Density (near r.t.)	12  g·cm−3
Melting point	1449 K (1176 °C, 2149 °F)
Boiling point	2880 K (2607 °C, 4725 °F)
Heat of fusion	14. This article is about the chemical element Curium for the ancient city also called Curium (located in Cyprus see Kourion Curium (ˈkjuːriəm Europium (jʊˈroʊpiəm is a Chemical element with the symbol Eu and Atomic number 63 This is a typical display of the periodic table of the elements and contains the symbol and Atomic number of each element Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of Chemical elements, sorted by name Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of chemical elements by symbol, including the A table of Chemical elements ordered by Atomic number and color coded according to type of element In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in History of the actinoid series From the earlier known chemical properties of actinium (89 up to uranium (92 indicating a relation to the Transition metals it was generally In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in In the Periodic table of the elements, a period is a horizontal row of the table A block of the Periodic table of elements is a set of adjacent groups The respective highest-energy electrons in each element in a block belong to the same Atomic Occurrence Scandium yttrium and the Lanthanides (except promethium tend to occur together in the Earth's crust and are relatively abundant compared with most D-block A period 7 element is one of the Chemical elements in the seventh row (or period) of the periodic table of the elements. The f-block of the Periodic table of the elements consists of those elements (sometimes referred to as the inner transition elements) for which in the The atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass To help compare different orders of magnitude, the following list describes various Mass levels between 10&minus36&thinsp kg and 1053&thinspkg In Atomic physics and Quantum chemistry, electron configuration is the arrangement of Electrons in an Atom, Molecule, or other Radon (ˈreɪdɒn is the Chemical element that has the symbol Rn and Atomic number 86 The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J An electron shell may be crudely thought of as an Orbit followed by Electrons around an Atom nucleus. In the Physical sciences a phase is a Set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties A solid' object is in the States of matter characterized by resistance to Deformation and changes of Volume. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed The melting point of a solid is the temperature range at which it changes state from solid to Liquid. The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 The standard Enthalpy of fusion (symbol \Delta{}H_{fus} also known as the heat of fusion or specific melting heat, is the amount of 39  kJ·mol−1
Specific heat capacity	(25 °C) 62. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the Temperature of a unit quantity 7  J·mol−1·K−1
Vapor pressure P(Pa) 1 10 100 1 k 10 k 100 k at T(K) 1239 1356
Atomic properties
Crystal structure	hexagonal
Oxidation states	6, 5, 4, 3 (amphoteric oxide)
Electronegativity	1. Vapor pressure (also known as equilibrium vapor pressure or saturation vapor pressure) is the Pressure of a Vapor in equilibrium In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. In Chemistry, the oxidation state is an indicator of the degree of Oxidation of an Atom in a Chemical compound. " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons 3 (Pauling scale)
Ionization energies	1st: 578 kJ/mol
Atomic radius	175  pm
Miscellaneous
Magnetic ordering	no data
Thermal conductivity	(300 K) 10  W·m−1·K−1
CAS registry number	7440-35-9
Selected isotopes
Main article: Isotopes of americium iso NA half-life DM DE (MeV) DP 241Am syn 432.2 y SF - - α 5. The ionization potential, ionization energy or EI of an Atom or Molecule is the Energy required to remove an Electron The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material Atomic radius, and more generally the size of an atom, is not a precisely defined Physical quantity, nor is it constant in all circumstances A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth In Physics, magnetism is one of the Phenomena by which Materials exert attractive or repulsive Forces on other Materials. In Physics, thermal conductivity, k is the property of a material that indicates its ability to conduct Heat. CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to Americium ( Am) has no stable Isotopes A standard atomic mass cannot be given Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides In Chemistry, natural abundance (NA refers to the abundance Isotopes of a Chemical element as naturally found on a planet Half-Life (computer-game page here It's already listed in the disambiguation page Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. The decay energy is the Energy released by a Nuclear decay. The energy difference of the Reactants is often written as Q: where Q In Nuclear physics, a decay product, also known as a daughter product, daughter isotope or daughter nuclide, is a Nuclide A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in To help compare Orders of magnitude of different times this page lists times between 1010 seconds and 1011 seconds (320 years and 3200 years Spontaneous fission (SF is a form of Radioactive decay characteristic of very heavy Isotopes and is theoretically possible for any atomic nucleus whose mass is greater Alpha decay is a type of radioactive decay in which an Atomic nucleus emits an Alpha particle (two protons and two neutrons bound together into a particle 638 237Np 242mAm syn 141 y IT 0. Neptunium (nɛpˈtjuːniəm is a Chemical element with the symbol Np and Atomic number 93 A nuclear isomer is a Metastable state of an Atomic nucleus caused by the excitation of one or more of its Nucleons A nuclear isomer occupies A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun Isomeric transition is a Radioactive decay process that occurs in an Atom where the nucleus is in an excited Meta state (e 049 - α 5. 637 238Np SF - - 243Am syn 7370 y SF - - α 5. Neptunium (nɛpˈtjuːniəm is a Chemical element with the symbol Np and Atomic number 93 A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in To help compare Orders of magnitude of different times this page lists times between 1011 seconds and 1012 seconds (3200 years and 32000 years See also 438 239Np
References

Americium (pronounced /ˌæməˈrɪsiəm/) is a synthetic element that has the symbol Am and atomic number 95. Neptunium (nɛpˈtjuːniəm is a Chemical element with the symbol Np and Atomic number 93 Recommended values for many properties of the elements together with various references are collected on these data pages In chemistry the Chemical elements labeled as synthetic are too unstable to be found naturally on Earth. See also List of elements by atomic number In Chemistry and Physics, the atomic number (also known as the proton A radioactive metallic element, americium is an actinide that was obtained in 1944 by bombarding plutonium with neutrons and was the fourth transuranic element to be discovered. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across History of the actinoid series From the earlier known chemical properties of actinium (89 up to uranium (92 indicating a relation to the Transition metals it was generally This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. In Chemistry, transuranium elements (also known as transuranic elements) are the Chemical elements with Atomic numbers greater than 92 (the atomic It was named for the Americas, by analogy with europium. The Americas are the lands of the Western hemisphere or New World, consisting of the Continents of North America and South America Europium (jʊˈroʊpiəm is a Chemical element with the symbol Eu and Atomic number 63

Contents 1 Properties 2 Applications 3 History 4 Isotopes 5 Chemistry 6 References 7 Further reading 8 External links

Properties

Main article: Actinides in the environment

Pure americium has a silvery and white lustre. Actinides in the environment refer to the sources environmental behaviour and effects of Actinides in the environment. Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. At room temperatures it slowly tarnishes in dry air. Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed It is more silvery than plutonium or neptunium and apparently more malleable than neptunium or uranium. Neptunium (nɛpˈtjuːniəm is a Chemical element with the symbol Np and Atomic number 93 Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the Alpha emission from ²⁴¹Am is approximately three times that of radium. Alpha decay is a type of radioactive decay in which an Atomic nucleus emits an Alpha particle (two protons and two neutrons bound together into a particle Radium (ˈreɪdiəm is a radioactive Chemical element which has the symbol Ra and Atomic number 88 Gram quantities of ²⁴¹Am emit intense gamma rays which creates a serious exposure problem for anyone handling the element. For other uses of the words gram or gramme see Gram (disambiguation. Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions

Americium is also fissile; the critical mass for an unreflected sphere of ²⁴¹Am is approximately 60 kilograms. In Nuclear engineering, a fissile material is one that is capable of sustaining a Chain reaction of Nuclear fission. It is unlikely that Americium would be used as a weapons material, as its minimum critical mass is considerably larger than more readily obtained plutonium or uranium isotopes. Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the ^[1]

Applications

This element can be produced in kilogram amounts and has some uses (mostly ²⁴¹Am since it is easier to produce relatively pure samples of this isotope). Americium is the only synthetic element to have found its way into the household, where one type of smoke detector contains a tiny amount (about 0. A smoke detector is a device that detects Smoke and issues an Alarm. 2 microgram) of ²⁴¹Am as a source of ionizing radiation. In the Metric system, a microgram is 1/1000000 of a Gram (1 × 10-6 or 1/1000 of a milligram is one of the smallest units of weight/mass commonly used Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation ²⁴¹Am has been used as a portable gamma ray source for use in radiography. For medical radiography see Radiology Radiography is the use of X-rays to view unseen or hard-to-image objects The element has also been employed to gauge glass thickness to help create flat glass. Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many ²⁴²Am is a neutron emitter and has found uses in neutron radiography as well as a neutron emitting radioactive source used in well logging applications (Am241Be). It has also been cited for use as an advanced nuclear rocket propulsion fuel. ^[2] This isotope is, however, extremely expensive to produce in usable quantities.

History

Americium was first isolated by Glenn T. Seaborg, Leon O. Glenn Theodore Seaborg ( Glenn Teodor Sjöberg) ( April 19, 1912 &ndash February 25, 1999) won the 1951 Nobel Prize in Chemistry Morgan, Ralph A. James, and Albert Ghiorso in late 1944 at the wartime Metallurgical Laboratory at the University of Chicago (now known as Argonne National Laboratory). Albert Ghiorso (born 15 July 1915) is an American nuclear scientist who helped discover numerous Chemical elements on the Periodic table Year 1944 ( MCMXLIV) was a Leap year starting on Saturday (link will display full calendar of the Gregorian calendar. The University of Chicago is a Private university located principally in the Hyde Park neighborhood of Chicago. Argonne National Laboratory is one of the United States Department of Energy 's oldest and largest science and engineering research national laboratories and is The team created the isotope ²⁴¹Am by subjecting ²³⁹Pu to successive neutron capture reactions in a nuclear reactor. Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides Neutron capture is a kind of Nuclear reaction in which an Atomic nucleus collides with one or more Neutrons and they merge to form a heavier nucleus This article is a subarticle of Nuclear power. A nuclear reactor is a device in which Nuclear chain reactions are initiated controlled This created ²⁴⁰Pu and then ²⁴¹Pu which in turn decayed into ²⁴¹Am via beta decay. In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted Seaborg was granted a patent for "Element 95 and Method of Producing Said Element," whose unusually terse claim number 1 reads simply, "Element 95. "^[3] The discovery of americium and curium was first announced informally on a children's quiz show in 1945. This article is about the chemical element Curium for the ancient city also called Curium (located in Cyprus see Kourion Curium (ˈkjuːriəm ^[4]

Isotopes

Main article: isotopes of americium

18 radioisotopes of americium have been characterized, with the most stable being ²⁴³Am with a half-life of 7370 years, and ²⁴¹Am with a half-life of 432. Americium ( Am) has no stable Isotopes A standard atomic mass cannot be given A radionuclide is an Atom with an unstable nucleus, which is a nucleus characterized by excess energy which is available to be imparted either to a newly-created Half-Life (computer-game page here It's already listed in the disambiguation page 2 years. All of the remaining radioactive isotopes have half-lives that are less than 51 hours, and the majority of these have half-lives that are less than 100 minutes. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. This element also has 8 meta states, with the most stable being ^242mAm (t_½ 141 years). A nuclear isomer is a Metastable state of an Atomic nucleus caused by the excitation of one or more of its Nucleons A nuclear isomer occupies The isotopes of americium range in atomic weight from 231. The atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass 046 u (²³¹Am) to 249. The unified atomic mass unit ( u) or Dalton ( Da) or sometimes universal mass unit, is an unit of Mass used to express 078 u (²⁴⁹Am).

Chemistry

In aqueous systems the most common oxidation state is +3. It is very much harder to oxidize Am(III) to Am(IV) than it is to oxidise Pu(III) to Pu(IV).

Currently the solvent extraction chemistry of americium is important as in several areas of the world scientists are working on reducing the medium term radiotoxicity of the waste from the reprocessing of used nuclear fuel. Liquid-liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds based on their relative solubilities in two A scientist, in the broadest sense refers to any person that engages in a systematic activity to acquire Knowledge or an individual that engages in such practices Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation Nuclear fuel is any material that can be consumed to derive Nuclear energy, by analogy to chemical Fuel that is burned to derive energy

See liquid-liquid extraction for some examples of the solvent extraction of americium. Liquid-liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds based on their relative solubilities in two

Americium dioxide is used in smoke detectors. ^[5]

Americium, unlike uranium, does not readily form a dioxide americyl core (AmO₂). ^[6] This is because americium is very hard to oxidise above the +3 oxidation state when it is in an aqueous solution. In the environment, this americyl core could complex with carbonate as well as other oxygen moieties (OH^-, NO₂^-, NO₃^-, and SO₄^-2) to form charged complexes which tend to be readily mobile with low affinities to soil.

• AmO₂(OH)⁺¹
• AmO₂(OH)₂⁺²
• AmO₂CO₃⁺¹
• AmO₂(CO₃)₂^-1
• AmO₂(CO₃)₃^-3

A large amount of work has been done on the solvent extraction of americium, as it is the case that americium and the other transplutonium elements are responsible for the majority of the long lived radiotoxicity of spent nuclear fuel. Liquid-liquid extraction, also known as solvent extraction and partitioning, is a method to separate compounds based on their relative solubilities in two Spent nuclear fuel, occasionally called used nuclear fuel, is Nuclear fuel that has been irradiated in a Nuclear reactor (usually at a Nuclear power It is thought that by removal of the americium and curium that the used fuel will only need to be isolated from man and his environment for a shorter time than that required for the isolation of untreated used fuel. This article is about the chemical element Curium for the ancient city also called Curium (located in Cyprus see Kourion Curium (ˈkjuːriəm One recent EU funded project on this topic was known by the codename "EUROPART". The European Union ( EU) is a political and economic union of twenty-seven member states, located primarily in Within this project triazines and other compounds were studied as potential extraction agents. A triazine is one of three Organic chemicals Isomeric with each other whose Empirical formula is 333 ^{[7][8][9][10][11]}

References

• WebElements.com - Americium

1. ^ Fissile Materials & Nuclear Weapons: Introduction. International Panel on Fissile Materials. Retrieved on 2007-11-22. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 498 - Kofi Aseidu- After the death of Anastasius II, Symmachus is elected Pope in the Lateran
2. ^ "Extremely Efficient Nuclear Fuel Could Take Man To Mars In Just Two Weeks", ScienceDaily, 3 Jan 2001. Dan Hogan Editoreditor@sciencedailycom Michele Hogan Sales Managersales@sciencedaily Retrieved on 2007-11-22. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 498 - Kofi Aseidu- After the death of Anastasius II, Symmachus is elected Pope in the Lateran  
3. ^ U.S. Patent 3,156,523 
4. ^ Rachel Sheremeta Pepling. It's Elemental: The Periodic Table: Americium. Chemical & Engineering News. Chemical & Engineering News is a weekly chemistry news magazine published by the American Chemical Society.
5. ^ Smoke Detectors and Americium
6. ^ David L. Clark (2000). "The Chemical Complexities of Plutonium" (Reprinted at fas. org). Los Alamos Science (26).  
7. ^ Michael J. Hudson, Michael G. B. Drew, Mark R. StJ. Foreman, Clément Hill, Nathalie Huet, Charles Madic and Tristan G. A. Youngs (2003). "The coordination chemistry of 1,2,4-triazinyl bipyridines with lanthanide(III) elements – implications for the partitioning of americium(III)". Dalton Trans.: 1675–1685. Dalton Transactions is a peer-reviewed Scientific journal publishing original (primary research and review articles on all aspects doi:10.1039/b301178j. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
8. ^ Andreas Geist, Michael Weigl, Udo Müllich, Klaus Gompper (11-13 Dec 2000). Actinide(III)/Lanthanide(III) Partitioning Using n-Pr-BTP as Extractant: Extraction Kinetics and Extraction Test in a Hollow Fiber Module. 6th Information Exchange Meeting on Actinide and Fission Product Partitioning and Transmutation. OECD Nuclear Energy Agency.
9. ^ C. Hill, D. Guillaneux, X. Hérès, N. Boubals and L. Ramain (24-26 Oct 2000). Sanex-BTP Process Development Studies. Atalante 2000: Scientific Research on the Back-end of the Fuel Cycle for the 21st Century. Commissariat à l'énergie atomique. The Commissariat à l’énergie atomique (Atomic Energy Commission or CEA, is a French “public establishment of an industrial and commercial character” whose
10. ^ Andreas Geist, Michael Weigl and Klaus Gompper (14-16 Oct 2002). Effective Actinide(III)-Lanthanide(III) Separation in Miniature Hollow Fibre Modules. 7th Information Exchange Meeting on Actinide and Fission Product Partitioning and Transmutation. OECD Nuclear Energy Agency.
11. ^ D. D. Ensor. Separation Studies of f-Elements. Tennessee Tech University. Tennessee Technological University, popularly known as Tennessee Tech, is an accredited Public university located in Cookeville Tennessee, US

Further reading

• Nuclides and Isotopes - 14th Edition, GE Nuclear Energy, 1989.
• Patent US3,156,523 (PDF version) (1964-11-10) Glenn T. Year 1964 ( MCMLXIV) was a Leap year starting on Wednesday (link will display full calendar of the 1964 Gregorian calendar. Events 1444 - Battle of Varna: The crusading forces of King Vladislaus III of Varna (aka Ulaszlo I of Hungary and Wladyslaw Seaborg Element 95 and Method of Producing Said Element 
• Gabriele Fioni, Michel Cribier and Frédéric Marie. Can the minor actinide, americium-241, be transmuted by thermal neutrons?. Commissariat à l'énergie atomique. The Commissariat à l’énergie atomique (Atomic Energy Commission or CEA, is a French “public establishment of an industrial and commercial character” whose
• Terry Kammash, David L. Galbraith, and Ta-Rong Jan (January 10, 1993). "An americium-fueled gas core nuclear rocket" in Tenth symposium on space nuclear power and propulsion. AIP Conf. Proc. 271: 585-589. doi:10.1063/1.43073. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  

External links

• Los Alamos National Laboratory - Americium
• Guide to the Elements - Revised Edition, Albert Stwertka, (Oxford University Press; 1998) ISBN 0-19-508083-1
• It's Elemental - Americium
• ATSDR - Public Health Statement: Americium

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