Difference between revisions of "Mendelevium" - New World Encyclopedia

Main article: Isotopes of mendelevium
101	fermium ← mendelevium → nobelium
	periodic table
General
Name, Symbol, Number	mendelevium, Md, 101
Chemical series	actinides
Group, Period, Block	n/a, 7, f
Appearance	unknown, probably silvery; white or metallic gray
Atomic mass	(258) g/mol
Electron configuration	[Rn] 5f13 7s2
Electrons per shell	2, 8, 18, 32, 31, 8, 2
Physical properties
Phase	solid
Melting point	1100 K; (827 °C, 1521 °F)
Atomic properties
Oxidation states	2, 3
Electronegativity	1.3 (Pauling scale)
Ionization energies	1st: 635 kJ/mol
Miscellaneous
Magnetic ordering	no data
CAS registry number	7440-11-1
Notable isotopes

Revision as of 23:59, 31 July 2007

Mendelevium (chemical symbol Md (formerly Mv), atomic number 101), also known as unnilunium (symbol Unu), is a synthetic element in the periodic table. A metallic radioactive transuranic element^[1] of the actinide series, mendelevium is synthesized by bombarding einsteinium with alpha particles. Only trace amounts of the element have been produced. The element is of interest mainly for research purposes, and practical applications have yet to be developed.

History

Mendelevium was named after Dmitri Mendeleev (surname also spelt as Mendeleyev, Mendeléef, or even Mendelejeff; first name sometimes spelt as Dmitry or Dmitriy). It was first synthesized by Albert Ghiorso (team leader), Glenn T. Seaborg, Bernard Harvey, Greg Choppin, and Stanley G. Thompson in early 1955 at the University of California, Berkeley. The team produced ²⁵⁶Md (half-life of 76 minutes) when they bombarded an ²⁵³Es target with alpha particles (helium nuclei) in the Berkeley Radiation Laboratory's 60-inch cyclotron (²⁵⁶Md was the first element to be synthesized one-atom-at-a-time). Element 101 was the ninth transuranic element synthesized.

Notable characteristics

Mendelevium is an inner transition metal of the actinide series, situated in period seven of the periodic table, between fermium and nobelium. Researchers have shown that mendelevium has a moderately stable dipositive (II) oxidation state in addition to the more characteristic (for actinide elements) tripositive (III) oxidation state. ²⁵⁶Md has been used to find out some of the chemical properties of this element while in an aqueous solution. Currently, there are no practical uses of mendelevium, and only trace amounts of the element have been produced.

Isotopes

15 radioisotopes of mendelevium have been characterized, with the most stable being ²⁵⁸Md with a half-life of 51.5 days, ²⁶⁰Md with a half-life of 31.8 days, and ²⁵⁷Md with a half-life of 5.52 hours. All of the remaining radioactive isotopes have half-lives that are less than 97 minutes, and the majority of these have half-lives that are less than five minutes. This element also has one meta state, ^258mMd (t_½ 57 minutes). The isotopes of mendelevium range in atomic weight from 245.091 amu (²⁴⁵Md) to 260.104 amu (²⁶⁰Md).

Notes

↑ "Transuranic elements" are the chemical elements with atomic numbers greater than that of uranium (atomic number 92).

References
ISBN links support NWE through referral fees

Emsley, John. Nature's Building Blocks: An A–Z Guide to the Elements. Oxford: Oxford Univ. Press, 2001. ISBN 0198503407

Greenwood, N.N., and A. Earnshaw. Chemistry of the Elements 2nd ed. Oxford, UK; Burlington, MA: Butterworth-Heinemann, 1998. ISBN 0750633654

Hampel, Clifford A. The Encyclopedia of the Chemical Elements. New York: Reinhold Book Corp, 1968. ISBN 0442155980

Morss, Lester R., Norman M. Edelstein, and Jean Fuger. The Chemistry of the Actinide and Transactinide Elements. 3rd ed. 5 vols. Joseph J. Katz, adapter. Dordrecht: Springer, 2006. ISBN 1402035551

Stwertka, Albert. Guide to the Elements. Rev. ed. Oxford: Oxford University Press, 1998. ISBN 0-19-508083-1.

External links

Chemistry Operations. 2003. Mendelevium Los Alamos National Laboratory, Chemistry Division. Retrieved July 31, 2007.
Winter, Mark. 2007. Mendelevium The University of Sheffield and WebElements Ltd. Retrieved July 31, 2007.
Thomas Jefferson National Accelerator Facility, Office of Science Education. 2007. It's Elemental: Mendelevium Jefferson Lab. Retrieved July 31, 2007.

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[1] "Transuranic elements" are the chemical elements with atomic numbers greater than that of uranium (atomic number 92).

[1]

@@ Line 1: / Line 1: @@
-{{Claimed}}{{Images OK}}{{Contracted}}{{Submitted}}{{Approved}}{{Paid}}
+{{Copyedited}}{{Claimed}}{{Images OK}}{{Contracted}}{{Submitted}}{{Approved}}{{Paid}}
 {{Elementbox_header | number=101 | symbol=Md | name=mendelevium | left=[[fermium]] | right=[[nobelium]] | above=[[thulium|Tm]] | below=(Upu) | color1=#ff99cc | color2=black }}
 {{Elementbox_series | [[actinide]]s }}
@@ Line 35: / Line 36: @@
 {{Elementbox_footer | color1=#ff99cc | color2=black }}
-'''Mendelevium''' (chemical  symbol '''Md''' (formerly '''Mv'''), [[atomic number]] 101), also known as '''unnilunium''' (symbol '''Unu'''), is a [[synthetic element]] in the [[periodic table]]. A [[metal]]lic  [[radioactive]] [[transuranic element]]<ref>"Transuranic elements" are the [[chemical element]]s with [[atomic number]]s greater than that of [[uranium]] (atomic number 92).</ref> of the [[actinide]] series, mendelevium is synthesized by bombarding [[einsteinium]] with [[alpha particle]]s. Only trace amounts of the element have been produced. The element is of interest mainly for research purposes, and practical applications have yet to be developed.
+'''Mendelevium''' (chemical symbol '''Md''' (formerly '''Mv'''), [[atomic number]] 101), also known as '''unnilunium''' (symbol '''Unu'''), is a [[synthetic element]] in the [[periodic table]]. A [[metal]]lic [[radioactive]] [[transuranic element]]<ref>"Transuranic elements" are the [[chemical element]]s with [[atomic number]]s greater than that of [[uranium]] (atomic number 92).</ref> of the [[actinide]] series, mendelevium is synthesized by bombarding [[einsteinium]] with [[alpha particle]]s. Only trace amounts of the element have been produced. The element is of interest mainly for research purposes, and practical applications have yet to be developed.
 == History ==
-Mendelevium was named after [[Dmitri Mendeleev]] (surname also spelt as Mendeleyev, Mendeléef, or even Mendelejeff; first name sometimes spelt as Dmitry or Dmitriy). It was first [[discovery of the chemical elements|synthesized]] by [[Albert Ghiorso]] (team leader), [[Glenn T. Seaborg]], [[Bernard Harvey]],[[Greg Choppin]], and [[Stanley G. Thompson]] in early 1955 at the University of California, Berkeley. The team produced <sup>256</sup>Md ([[half-life]] of 76 minutes) when they bombarded an <sup>253</sup>[[einsteinium|Es]] target with [[alpha particle]]s ([[helium]] nuclei) in the [[Berkeley Radiation Laboratory]]'s 60-inch [[cyclotron]] (<sup>256</sup>Md was the first element to be synthesized one-atom-at-a-time). Element 101 was the ninth [[transuranic element]] synthesized.
+Mendelevium was named after [[Dmitri Mendeleev]] (surname also spelt as Mendeleyev, Mendeléef, or even Mendelejeff; first name sometimes spelt as Dmitry or Dmitriy). It was first [[discovery of the chemical elements|synthesized]] by [[Albert Ghiorso]] (team leader), [[Glenn T. Seaborg]], [[Bernard Harvey]], [[Greg Choppin]], and [[Stanley G. Thompson]] in early 1955 at the University of California, Berkeley. The team produced <sup>256</sup>Md ([[half-life]] of 76 minutes) when they bombarded an <sup>253</sup>[[einsteinium|Es]] target with [[alpha particle]]s ([[helium]] nuclei) in the [[Berkeley Radiation Laboratory]]'s 60-inch [[cyclotron]] (<sup>256</sup>Md was the first element to be synthesized one-atom-at-a-time). Element 101 was the ninth [[transuranic element]] synthesized.
 == Notable characteristics ==
-Mendelevium is an [[inner transition metal]] of the actinide series, situated in period 7 of the [[periodic table]], between [[fermium]] and [[nobelium]]. Researchers have shown that mendelevium has a moderately stable dipositive (II) [[oxidation state]] in addition to the more characteristic (for actinide elements) tripositive (III) oxidation state. <sup>256</sup>Md has been used to find out  some of the chemical properties of this element while in an [[aqueous]] solution. Currently, there are no practical uses of mendelevium, and only trace amounts of the element have been produced.
+Mendelevium is an [[inner transition metal]] of the actinide series, situated in period seven of the [[periodic table]], between [[fermium]] and [[nobelium]]. Researchers have shown that mendelevium has a moderately stable dipositive (II) [[oxidation state]] in addition to the more characteristic (for actinide elements) tripositive (III) oxidation state. <sup>256</sup>Md has been used to find out some of the chemical properties of this element while in an [[aqueous]] solution. Currently, there are no practical uses of mendelevium, and only trace amounts of the element have been produced.
 === Isotopes ===
-[[radioisotope]]s of mendelevium have been characterized, with the most stable being <sup>258</sup>Md with a [[half-life]] of 51.5 days, <sup>260</sup>Md with a half-life of 31.8 days, and <sup>257</sup>Md with a half-life of 5.52 hours. All of the remaining [[radioactive]] isotopes have half-lives that are less than 97 minutes, and the majority of these have half-lives that are less than 5 minutes. This element also has 1 [[meta state]], <sup>258m</sup>Md (t<sub>½</sub> 57 minutes). The isotopes of mendelevium range in [[atomic weight]] from 245.091 [[atomic mass unit|amu]] (<sup>245</sup>Md) to 260.104 amu (<sup>260</sup>Md).
+[[radioisotope]]s of mendelevium have been characterized, with the most stable being <sup>258</sup>Md with a [[half-life]] of 51.5 days, <sup>260</sup>Md with a half-life of 31.8 days, and <sup>257</sup>Md with a half-life of 5.52 hours. All of the remaining [[radioactive]] isotopes have half-lives that are less than 97 minutes, and the majority of these have half-lives that are less than five minutes. This element also has one [[meta state]], <sup>258m</sup>Md (t<sub>½</sub> 57 minutes). The isotopes of mendelevium range in [[atomic weight]] from 245.091 [[atomic mass unit|amu]] (<sup>245</sup>Md) to 260.104 amu (<sup>260</sup>Md).
 == See also ==
@@ Line 62: / Line 63: @@
 ==References==
-* Emsley, John. 2001. ''Nature's Building Blocks: An A&ndash;Z Guide to the Elements''. Oxford: Oxford Univ. Press. ISBN 0198503407 and ISBN 978-0198503408.
+* Emsley, John. ''Nature's Building Blocks: An A&ndash;Z Guide to the Elements''. Oxford: Oxford Univ. Press, 2001. ISBN 0198503407
-* Greenwood, N.N., and A. Earnshaw. 1998. ''Chemistry of the Elements'' 2nd ed. Oxford, UK; Burlington, MA: Butterworth-Heinemann. ISBN 0750633654. [http://www.knovel.com/knovel2/Toc.jsp?BookID=402&VerticalID=0 Online version].
+* Greenwood, N.N., and A. Earnshaw. ''Chemistry of the Elements'' 2nd ed. Oxford, UK; Burlington, MA: Butterworth-Heinemann, 1998. ISBN 0750633654
-* Hampel, Clifford A. 1968. ''The Encyclopedia of the Chemical Elements''. New York: Reinhold Book Corp. ISBN 0442155980 and ISBN 978-0442155988.
+* Hampel, Clifford A. ''The Encyclopedia of the Chemical Elements''. New York: Reinhold Book Corp, 1968. ISBN 0442155980
-* Morss, Lester R., Norman M. Edelstein, and Jean Fuger, eds. 2006. ''The Chemistry of the Actinide and Transactinide Elements''. 3rd ed. 5 vols. Joseph J. Katz, adapter. Dordrecht: Springer. ISBN 1402035551 and ISBN 978-1402035555.
+* Morss, Lester R., Norman M. Edelstein, and Jean Fuger. ''The Chemistry of the Actinide and Transactinide Elements''. 3rd ed. 5 vols. Joseph J. Katz, adapter. Dordrecht: Springer, 2006. ISBN 1402035551
-* Stwertka, Albert. 1998. ''Guide to the Elements''. Rev. ed. Oxford: Oxford University Press. ISBN 0-19-508083-1.
+* Stwertka, Albert. ''Guide to the Elements''. Rev. ed. Oxford: Oxford University Press, 1998. ISBN 0-19-508083-1.
 == External links ==
-* Chemistry Operations. 2003. [http://periodic.lanl.gov/elements/101.html Mendelevium.] ''Los Alamos National Laboratory, Chemistry Division''. Retrieved March 16, 2007.
+* Chemistry Operations. 2003. [http://periodic.lanl.gov/elements/101.html Mendelevium] ''Los Alamos National Laboratory, Chemistry Division''. Retrieved July 31, 2007.
-* Winter, Mark. 2007. [http://www.webelements.com/webelements/elements/text/Md/index.html Mendelevium.] ''The University of Sheffield and WebElements Ltd.'' Retrieved March 16, 2007.
+* Winter, Mark. 2007. [http://www.webelements.com/webelements/elements/text/Md/index.html Mendelevium] ''The University of Sheffield and WebElements Ltd.'' Retrieved July 31, 2007.
-* Thomas Jefferson National Accelerator Facility, Office of Science Education. 2007. [http://education.jlab.org/itselemental/ele101.html It's Elemental: Mendelevium.] ''Jefferson Lab''. Retrieved March 16, 2007.
+* Thomas Jefferson National Accelerator Facility, Office of Science Education. 2007. [http://education.jlab.org/itselemental/ele101.html It's Elemental: Mendelevium] ''Jefferson Lab''. Retrieved July 31, 2007.
 [[Category:Physical sciences]]