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Topic: Discoveries of the chemical elements


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  WebElements Chemistry Books Store (USA) - A Guide to the Elements   (Site not responding. Last check: 2007-10-17)
Newly updated with the stunning discovery of two new elements, A Guide to the Elements, 2nd Edition is still the easy-to-read, easy-to-understand resource to the periodic table that students and teachers of the physical sciences expect.
A Guide to the Elements, Second Edition begins with an introductory section that explains some of the basic concepts of chemistry and traces the history and development of the periodic table of the elements.
There are at least 112 chemical elements, all of which but a few comprise the entire world as we know it.
astore.amazon.com /webelements/detail/0195150260   (1036 words)

  
  Learn more about Discoveries of the chemical elements in the online encyclopedia.   (Site not responding. Last check: 2007-10-17)
The elements are listed generally in the order in which they were first isolated as the pure element, rather than as a compound (some such as boron were known to be elements decades before they could be isolated from their compounds).
The elements labelled as "synthetic" are unstable, with a half-life so "short" relative to the age of the earth that any atoms of that element that may have been present when the earth formed, have long since completely decayed away.
The discovery of technetium finally filled in a puzzling gap in the periodic table, and the discovery that there were no stable isotopes of technetium explained its absence on earth: its 4.2 million years half-life meant that none remained from the time of formation of the earth.
www.onlineencyclopedia.org /d/di/discoveries_of_the_chemical_elements.html   (1207 words)

  
 Education Resources » Chemistry
Chemical phenomena are associated with a change in the properties of the substance as a result of a chemical reaction.
A chemical reaction is often accompanied by evolution or absorption of energy, this phenomenon is studied under a subdiscipline of chemistry called chemical thermodynamics/ thermochemistry.
For example, all atoms with 6 protons in their nuclei are atoms of the chemical element carbon, and all atoms with 92 protons in their nuclei are atoms of the element uranium.
www.thecatalyst.org /resource/2006/04/21/Chemistry   (2327 words)

  
 Periodic table - Biocrawler   (Site not responding. Last check: 2007-10-17)
The periodic table of the chemical elements, also called the Mendeleev periodic table, is a tabular display of the known chemical elements.
However, Mendeleev plotted a few elements out of strict mass sequence in order to make a better match to the properties of their neighbours in the table, corrected mistakes in the values of several atomic masses, and predicted the existence and properties of a few new elements in the empty cells of his table.
Mendeleev was later vindicated by the discovery of the electronic structure of the elements in the late 19th and early 20th century.
www.biocrawler.com /encyclopedia/Periodic_table   (1156 words)

  
 History of the Origin of the Chemical Elements and Their Discoverers
The method of discovery of the chemical elements in the late eighteenth and the early nineteenth centuries used the properties of the new substances, their separability, the colors of their compounds, the shapes of their crystals and their reactivity to determine the existence of new elements.
Elements exist where the accepted name was proposed on the basis of an erroneous discovery of that element but widespread usage has dictated the continued use of the original name, even after the error has been discovered (see nobelium in the element list).
It is the eighth element in the Actinide series of the elements and was named in analogy with Terbium (for Ytterby the town in Sweden whose mine produced the ore), which is the eighth element in the Lanthanide series of the elements.
www.nndc.bnl.gov /content/elements.html   (11235 words)

  
 PERIODIC TABLE FACTS AND INFORMATION   (Site not responding. Last check: 2007-10-17)
The periodic table of the chemical elements is a tabular method of displaying the chemical elements, first devised in 1869 by the Russian chemist Dmitri Mendeleev.
Modern quantum mechanical theories of atomic structure explain that elements within the same group have the same electron configurations in their valence shell, which is the largest factor in accounting for their similar chemical properties.
Progressing through a group from lightest element to heaviest element, the outer-shell electrons (those most readily accessible for participation in chemical reactions) are all in the same type of orbital, with a similar shape, but with increasingly higher energy and average distance from the nucleus.
www.splammer.com /?req=periodic_table   (1659 words)

  
 Britain.tv Wikipedia - Chemist
Biochemistry is the study of the chemicals, chemical reactions and chemical interactions that take place in living organisms.
It was fire that led to the discovery of iron and glass.
The discoveries of the chemical elements has a long history culminating in the creation of the periodic table by Dmitri Mendeleyev.
www.britain.tv /wikipedia.php?title=Chemist   (994 words)

  
 Periodic table: Encyclopedia of chemistry, analytics & pharmaceutics with 64,564 entries.
The periodic table of the chemical elements is a tabular method of displaying the chemical elements, first devised by English analytical chemist John Newlands in 1863.
Elements 43 (technetium) and 61 (promethium), although of lower atomic number than the naturally occurring element 92, uranium, are synthetic; elements 93 (neptunium) and 94 (plutonium) are listed with the synthetic elements, but have been found in trace amounts on earth.
Mendeleev was later vindicated by the discovery of the electronic structure of the elements in the late 19th and early 20th century.
www.chemie.de /lexikon/e/Periodic_table   (2493 words)

  
 MONATOMIC ELEMENTS
To detect a monatomic element requires that you first convert it from its monatomic state to its normal state to allow the element to be detected with conventional instrumentation.
This stirring action of ORMUS elements may be causing the fluid of empty space to transform itself into the nectar of immortality that serves as the Essence of life itself.
Because they are chemically inert, their effects cannot be due to chemical reactions in the body, but due to an energetic effect.
www.crucible.org /monatomic_elements.htm   (5754 words)

  
 Discoveries of the chemical elements   (Site not responding. Last check: 2007-10-17)
The next element discovered when Mosander showed the cerium isolated in 1803 by Berzelius was actually a mixture cerium lanthanum and so-called didymium (which was actually one element and was resolved into in 1885).
The so-called "synthetic" elements are unstable with half-lives so "short" relative to the age the earth that any atoms of that that may have been present when the formed have long since completely decayed away.
The discovery of technetium finally filled a puzzling gap in the periodic table and the discovery that there were stable isotopes of technetium explained its absence earth: its 4.2 million years half-life meant that none remained from time of formation of the earth.
www.freeglossary.com /Discovery_of_the_chemical_elements   (1392 words)

  
 The Structure of Scientific Revolutions   (Site not responding. Last check: 2007-10-17)
I have, for example, previously referred to the discoveries of new chemical elements during the second half of the nineteenth century as proceeding from normal science in that way.
that discovery is not quite the one anticipated by the speculative and tentative hypothesis.
One of the competing schools of electricians took electricity to be a fluid, and that conception led a number of men to attempt bottling the fluid by holding a water-filled glass vial in their hands and touching the water to a conductor suspended from an active electrostatic generator.
www.tfcbooks.com /mall/more/101ssr.htm   (1627 words)

  
 The Periodic Table — FactMonster.com
Although some elements, such as gold and iron, have been known to humans since prehistoric times, it wasn't until the 17th century that the first scientific discovery of an element (phosphorus) was made.
Only 12 elements were known prior to 1700, but as more and more elements were discovered—by 1900 there were more than 80—scientists tried to find a way to organize them systematically, according to their physical and chemical properties.
De Chancourtois was the first to notice the periodicity of the elements, that is, when the elements were arranged according to their atomic weights, similar elements seemed to occur at regular intervals.
www.factmonster.com /ipka/A0905215.html   (973 words)

  
 directopedia : Directory : Science : Chemistry
More central to chemistry is the interaction of one substance with another such as in the classic chemical reaction where one substance is transformed into another; or with electromagnetic radiation (as in photochemistry).
A chemical reaction is often accompanied by evolution of absorbtion of energy, this phenomenon is studied under a subdiscipline of chemistry called chemical thermodynamics/ thermochemistry.
A compound is a substance with a fixed ratio of chemical elements which determines the composition, and a particular organisation which determines chemical properties.
www.directopedia.org /directory/Science-Chemistry.shtml   (2960 words)

  
 Discoveries of the chemical elements - Wikipedia, the free encyclopedia
The elements are listed generally in the order in which each was first isolated as the pure element, rather than found within a compound (some such as boron were known to be elements decades before they could be isolated from their compounds).
Because of his belief in phlogiston, Priestley did not realise that he had prepared a new element, and thought that he had managed to prepare air free from phlogiston ("de-phlogisticated air").
The didymium isolated by Mosander in 1839 was shown to be two separate elements, praseodymium and neodymium.
en.wikipedia.org /wiki/Discoveries_of_the_chemical_elements   (651 words)

  
 C&EN: IT'S ELEMENTAL: THE PERIODIC TABLE - INTRODUCTION
What has always struck me as remarkable about Dmitry Mendeleyev’s discovery in 1869 of a way to arrange the elements known at that time into a meaningful and predictive periodic table is that he accomplished it without any knowledge of the structure of atoms.
New elements were discovered that filled in the holes Mendeleyev left in his table, and their atomic weights and chemical properties corresponded with remarkable accuracy to Mendeleyev’s predictions.
And as the revolution in chemistry and physics unfolded in the early decades of the 20th century, most of the discoveries about the structure of atoms, their properties, and how they interact with each other made perfect sense in light of the periodic table.
pubs.acs.org /cen/80th/elements.html   (487 words)

  
 ASTROPHYSICS: ON STELLAR SYNTHESIS OF CHEMICAL COMPOUNDS
These newly synthesized elements are raised to the surface through periodic "dredge-up" episodes, and the observation of short-lived isotopes in stellar atmospheres provides direct evidence that nucleosynthesis is occurring in AGB stars(2).
The discovery of a large number of gas-phase molecules as well as submicrometer-sized solid-state particles of various chemical compositions in the circumstellar envelopes of AGB stars has led to the realization that extensive molecular synthesis occurs during this brief phase of stellar evolution.
The chemical composition of the interstellar medium is dominated by neutral hydrogen (93.38%) and helium (6.49%), whereas biogenic elements oxygen, carbon, and nitrogen contribute 0.11% (O:C:N 7:3:1).
scienceweek.com /2004/sa041210-1.htm   (1395 words)

  
 35. On the Track of False Suns   (Site not responding. Last check: 2007-10-17)
Long and thorny was the path of the discoverers of new elements, like a path through a thicket which keeps losing itself among narrow crevices.
But the latter was the track of false suns, of false discoveries of chemical elements.
Swienne, a German scientist, sought the transuranium elements in samples of that was thought to be cosmic dust collected among the glaciers of Greenland by the famous polar explorer Nordenskjold.
www.todayinsci.com /stories/story035a.htm   (258 words)

  
 The Science Channel :: 100 Greatest Discoveries: Chemistry   (Site not responding. Last check: 2007-10-17)
Thus, a pure element consists of identical atoms, all with the same mass, and compounds consist of atoms of different elements combined together.
Dmitry Mendeleyev realizes that if all of the 63 known elements are arranged in order of increasing atomic weight, their properties are repeated according to certain periodic cycles.
Niels Bohr publishes his model of atomic structure in which electrons travel in specific orbits around the nucleus, and the chemical properties of an element are largely determined by the number of electrons in its atoms' outer orbits.
science.discovery.com /convergence/100discoveries/big100/chemistry.html   (725 words)

  
 Talk:Discoveries of the chemical elements - Wikipedia, the free encyclopedia
This article says Francium was the "last naturally occurring element discovered" (1939), then says Astatine was discovered in 1940.
I don't know much about the history of the discoveries of elements, so I don't know why berylium is listed twice: 1798 and 1828.
On the page Carl Wilhelm Scheele it is also stated that he "also discovered other chemical elements such as barium (1774), chlorine (1774), manganese (1774), molybdenum (1778), and tungsten (1781)".
en.wikipedia.org /wiki/Talk:Discoveries_of_the_chemical_elements   (238 words)

  
 Elements--Physical Science lesson plan (grades 6-8)--DiscoverySchool.com   (Site not responding. Last check: 2007-10-17)
Debate whether an element that is made by scientists in a linear accelerator by the collision of high-speed particles and that exists for only a fraction of a second should be considered an element.
When their research is complete, ask each team to express its new knowledge of the elemental group they have studied by writing and performing skits in which they personify each of the elements in their assigned group.
Definition: A medieval chemical science and speculative philosophy aiming to achieve the transmutation of the base metals into gold, the discovery of a universal cure for disease, and the discovery of a means of indefinitely prolonging life.
school.discovery.com /lessonplans/programs/elements   (1737 words)

  
 The elemenents of the periodic table sorted by the discovery year
The elements of the periodic table sorted by the discovery year
The oldest chemical element is Phosphorus and the newest element is Hassium.
Please note that the elements do not show their natural relation towards each other as in the Periodic system.
www.lenntech.com /Periodic-chart-elements/discovery-year.htm   (163 words)

  
 PSR Discoveries: Hot Idea: Moonbeams and Elements
These two elements are especially useful in understanding the origin and geological evolution of the Moon.
Titanium is an important probe of the compositions of magmas because it does not enter most minerals; instead it builds up in a magma during crystallization, so its abundance is a measure of the amount of crystallization that took place before a given rock formed in a large body of magma.
Most important, the two elements allow us to distinguish among the known types of lunar rocks, and titanium forms the basis for classifying the basalts that make up the lunar maria.
www.psrd.hawaii.edu /Oct97/MoonFeO.html   (1929 words)

  
 Berkeley Lab Designated Historical Landmark by American Chemical Society
Their efforts culminated in 1999 with the synthesis of elements 118, 116, and 114, extending the Periodic Table to a long-sought region of nuclear stability poetically dubbed The Island of Superheavy Elements."
Darleane Hoffman, a chemist in Berkeley Lab's Nuclear Science Division, a codiscoverer of several of these elements and this year's recipient of the Priestley Medal, the ACS' highest honor, served as master of ceremonies for the event.
Said Busch, "The discovery of these elements advanced the frontiers of science (and) also illustrates the impact on science both of a great man and a great team.
www.lbl.gov /Science-Articles/Archive/chemical-landmarks.html   (279 words)

  
 Discovery and Naming of Chemical Elements
This is an effort to present the history of the discovery of the chemical elements and the origins of their names in a way that is both useful and interesting.
The information has been updated to include recently discovered elements and greatly expanded to include information about the discoveries and the people responsible.
has an extensive etymology of the names of the chemical elements, their names in over 70 languages, and some photographs at www.vanderkrogt.net/elements.
homepage.mac.com /dtrapp/Elements/elements.html   (332 words)

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