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Topic: Protactinium

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	It's Elemental - The Element Protactinium
		Protactinium was first identified by Kasimir Fajans and O.H. Göhring in 1913 while studying uranium's decay chain.
		Protactinium's existence was confirmed in 1918 when another isotope, protactinium-231, was independently discovered and studied by two groups of scientists, Otto Hahn and Lise Meitner of Germany and Frederick Soddy and John Cranston of Great Britain.
		Protactinium is a rare, poisonous and expensive element that is present in uranium ores in very small amounts.
	education.jlab.org /itselemental/ele091.html (187 words)

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	Highbeam Encyclopedia - Search Results for Protactinium
		Periodic Table of the Elements: Protactinium
		protactinium (symbol Pa) Rare radioactive metallic element of the actinide series, first identified in 1913.
		ruthenium, uranium, europium, zirconium, lutetium, vanadium, and lanthanum, and osmium, and astatine, and radium, and gold, and protactinium, and indium, and gallium, and iodine, and thorium, and thulium, and thallium.
	www.encyclopedia.com /SearchResults.aspx?Q=Protactinium (785 words)

	Protactinium - Definition, explanation
		Protactinium is a chemical element in the periodic table that has the symbol Pa and atomic number 91.
		Protactinium is a silver metallic element that belongs to the actinide group, with a bright metallic luster that it retains for some time in the air.
		Protactinium occurs in pitchblende to the extent of about 1 part 231-Pa to 10 million of ore; ores from Zaire have about 3 ppm.
	www.calsky.com /lexikon/en/txt/p/pr/protactinium.php (452 words)

	Protactinium (Pa) - Chemical properties, Health and Environmental effects
		Protactinium is a silver metallic element that belongs to the actinide group.
		Protactinium is naturally present in soil, rock, surface water, groundwater, plants and animals in very low concentrations (on the order of 1 ppt or 0.1 picocouries (pCi)/g).
		Protactinium preferentially adheres quite well to soil, and the concentration associated with sandy soil particles is typically 550 times higher than in interstitial water (water in the pore space between the soil particles); concentration ratios are even higher (about 2,000 and above) for loam and clay soils.
	www.lenntech.com /Periodic-chart-elements/Pa-en.htm (737 words)

	AllRefer.com - protactinium, Compound & Element (Compounds And Elements) - Encyclopedia
		The most stable is protactinium-231 (half-life about 32,500 years); it is also the most common, being found in nature in all uranium ores in about the same abundance as radium.
		Protactinium has been called the "mother" of actinium, which is formed by the alpha decay of protactinium.
		The first discovery of protactinium was in 1913 by Kasimir Fajans and O. GOhring, who found the isotope protactinium-234m (half-life 1.2 min), a decay product of uranium-238; they named it brevium for its short life.
	reference.allrefer.com /encyclopedia/P/protacti.html (286 words)

	Pa - Protactinium
		The nameprotoactinium was shortened to protactinium in 1949.
		Protactinium has 20 isotopes, the most common of which is 231Pa with ahalf-life of 32,700 years.
		A number of protactinium compounds are known, some of which arecolored.
	www.physlink.com /Reference/ChemicalElements/protactinium.cfm (304 words)

	WHOI : Media Relations : News Release : Fine-tuning the Steps in the Intricate Climate Change Dance (Site not responding. Last check: )
		Using the same technique that compares the abundance of two naturally occurring isotopes, protactinium and thorium, she compared the temperature record of an ice core from Greenland to a sediment core collected on the Blake Outer Ridge off the east coast of the United States.
		Protactinium and thorium are daughter isotopes of naturally occurring uranium in seawater.
		Protactinium (Pa) is removed less readily and thus remains in the water column 100 to 200 years.
	www.whoi.edu /mr/pr.do?id=8839 (1083 words)

	Proactinium (Pa) (Site not responding. Last check: )
		Protactinium is a radioactive metallic element and a member of the actinide series of the periodic table.
		Protactinium was identified first in 1913 by K. Fajans and O. Gohring who named it "brevium".
		Protactinium has a bright metallic luster which lasts for sometime in air.
	www.bayerus.com /msms/fun/pages/periodic/protactinium/index.html (88 words)

	Principal Metals-Protactinium
		Later, in 1934, from 0.1 g of pure Pa2O5 he isolated the element by two methods, one of which was by converting the oxide to an iodide and "cracking" it in a high vacuum by an electrically heated filament by the reaction: 2PaI5 --> 2Pa + 5I2.
		Protactinium has 20 isotopes, the most common of which is 231Pa with a half-life of 32,700 years.
		Protactinium is one of the rarest and most expensive naturally occurring elements.
	www.principalmetals.com /utilities/91.htm (330 words)

	The Elements: Protactinium (Site not responding. Last check: )
		Protactinium has a bright metallic luster which it retains for some time in air.
		Protactinium has thirteen isotopes, the most common of which is Pr(231) with a half-life of 32,500 yrs.
		A number of protactinium compounds are known, some of which are colored.
	www.cmbi.kun.nl /~ott/elements/protactinium.html (238 words)

	C&EN: IT'S ELEMENTAL: THE PERIODIC TABLE - PROTACTINIUM
		Soddy was one of the discoverers of protactinium, but this was a minor accomplishment, considering that it was Soddy who elucidated the concept of isotopes--the existence of elements of identical chemical properties yet different atomic masses--for which he received the 1921 Nobel Prize in Chemistry.
		Soddy also theorized and then proved that radioactivity is accompanied by a chemical "transmutation" of the elements--that is, one element changing into another element by nuclear decay.
		Protactinium was first identified by Kasimir Fajans and O. Göhring in 1913 while they were studying uranium's decay.
	pubs.acs.org /cen/80th/protactinium.html (691 words)

	Periodic Table : Scholar edition: protactinium : Compounds
		Electronegativity is a measure of the ability of an atom within a molecule to attract electrons to itself.
		In compounds of protactinium (where known), the most common oxidation numbers of protactinium are: 5.
		For each compound, a formal oxidation number for protactinium is given, but the usefulness of this number is limited for p-block elements in particular.
	www.webelements.com /webelements/scholar/elements/protactinium/compounds.html (345 words)

	Rate of ocean circulation directly linked to abrupt climate change
		The isotopes, protactinium and thorium, are produced at constant rates in seawater by radioactive decay from dissolved uranium and are removed quickly by adhering to particles settling to the ocean floor.
		Protactinium is removed less readily and thus remains in the water column 100 to 200 years.
		As a result, about half of the protactinium produced in North Atlantic water today is exported into the Southern Ocean as part of the ocean circulation system known as the great conveyor.
	www.eurekalert.org /pub_releases/2004-04/whoi-roo042204.php (739 words)

	Protactinium (Site not responding. Last check: )
		Protactinium is a member of the actinide series of the periodic table.
		Protactinium is a member of the uranium-actinium radioactive-decay series and is found in uranium ores.
		Isotopes of protactinium ranging in mass number from 215 to 238 are known.
	www.cartage.org.lb /en/themes/Sciences/Chemistry/NuclearChemistry/Transuranium/protactinium.html (134 words)

	Protactinium
		Later, in 1934, from 0.1 g of pure Pa2O5 he isolated the element by two methods, one of which was by converting the oxide to an iodide and "cracking" it in a high vacuum by an electrically heated filament by the reaction: 2PaI5 --> 2Pa + 5I2.
		Protactinium has a brigh metallic luster which it retains for some time in air.
		Protactinium has 20 isotopes, the most common of which is 231Pa with a half-life of 32,700 years.
	www.corrosionsource.com /handbook/periodic/91.htm (330 words)

	Protactinium (Site not responding. Last check: )
		Protactinium is found mixed with uranium ores such as pitchblende.
		Protactinium is a heavy, silvery-white and shiny metal.
		Because the metal, as well as all of its compounds, is radioactive and poisonous, the element has no commercial application.
	nobel.scas.bcit.ca /resource/ptable/pa.htm (185 words)

	Chemistry : Periodic Table : protactinium : key information
		Protactinium has a bright metallic lustre which it retains for some time in air.
		Protactinium is one of the rarest and most expensive naturally occurring elements.
		Protactinium is a highly toxic and radioactive rare earth metal that requires special handling.
	www.webelements.com /webelements/elements/text/Pa/key.html (190 words)

	protactinium — FactMonster.com
		The first discovery of protactinium was in 1913 by Kasimir Fajans and O. Göhring, who found the isotope protactinium-234m (half-life 1.2 min), a decay product of uranium-238; they named it brevium for its short life.
		Periodic Table of the Elements: Protactinium - Periodic Table of the Elements: Protactinium 91 Pa Protactinium 231.0359 2 · 8 · 18...
		Pa - Pa Pa, symbol for the element protactinium.
	www.factmonster.com /ce6/sci/A0840296.html (213 words)

	Facts about Protactinium
		Protactinium classified as an element in the Actinide series as one of the "Rare Earth Elements" which can located in Group 3 elements of the Periodic Table and in the 6th and 7th periods.
		Find out more facts about Protactinium on the Periodic Table which arranges every chemical element according to its atomic number, as based on the periodic law, so that chemical elements with similar properties are in the same column.
		The famous Russian Scientist, Dimitri Mendeleev, perceived the correct classification method of "the periodic table" for the 65 elements which were known in his time.
	www.facts-about.org.uk /science-element-protactinium.htm (378 words)

	Protactinium: Chemical Elements
		Protactinium is one of the rarest elements on Earth.
		For many years, the only supply of protactinium of any size was kept in Great Britain.
		Protactinium belongs in the actinides series in the periodic table.
	science.enotes.com /chemical-elements/protactinium (142 words)

	protactinium - OneLook Dictionary Search
		protactinium : Compact Oxford English Dictionary [home, info]
		Protactinium, protactinium : WebElements Periodic Table of the Elements [home, info]
		Words similar to protactinium: pa, protoactinium, atomic number 91, more...
	www.onelook.com /?w=protactinium (196 words)

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In the News (Fri 27 Nov 09)