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Topic: Chemical element

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  Chemistry: WebElements Periodic Table
The periodic "law" of chemistry recognises that many properties of the chemical elements are periodic functions of their atomic number (the number of protons within the element's atomic nucleus).
The periodic table is an arrangement of the chemical elements ordered by atomic number in columns (groups) and rows (periods) presented so as to emphasize their periodic properties.
The element polonium is very much in the news at present, perhaps for the first time ever, and for the wrong reasons.
www.webelements.com   (426 words)

  Elements - MSN Encarta
A group of elements called metalloids, intermediate in properties between the metals and the nonmetals, are sometimes considered a separate class.
When the elements are arranged in the order of their atomic numbers (a number proportional to the net positive charge on the nucleus of an atom of an element), elements of similar physical and chemical properties occur at specific intervals (see Periodic Law).
These groups of elements with similar physical and chemical properties are called families, examples of which are the alkaline earth metals, rare earth elements, halogens, and the noble gases.
encarta.msn.com /encyclopedia_761564544/Elements.html   (468 words)

  Chemical element - Wikipedia, the free encyclopedia
The atomic mass of an element, A, is measured in unified atomic mass units (u) is the average mass of all the atoms of the element in an environment of interest (usually the earth's crust and atmosphere).
The 23 elements not found on earth are derived artificially; the first purportedly synthesized element was technetium, in 1937, although the trace amounts of naturally occurring technetium were not known then.
The naming of elements precedes the atomic theory of matter, although at the time it was not known which chemicals were elements and which compounds.
en.wikipedia.org /wiki/Chemical_element   (1395 words)

 Chemical Reaction - MSN Encarta
Chemical Reaction, process by which atoms or groups of atoms are redistributed, resulting in a change in the molecular composition of substances.
Symbols for the elements may be used merely as abbreviations for the name of the element, but they are used more commonly in formulas and equations to represent a fixed relative quantity of the element.
The atomic number of an element is equal to the number of protons in the nucleus of an atom of the element.
encarta.msn.com /encyclopedia_761573235/Chemical_Reaction.html   (1485 words)

 Chemical element - Wikipedia
A chemical element (sometimes called simply element) is a material that consists of atoms with the same number of protons in the nucleus.
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.
Chemical elements are also given a unique chemical symbol, often based on the name of the element,not necessarily in English (for example, carbon has chemical symbol 'C', and sodium has chemical symbol 'Na' after the Latin natrium).
wikipedia.findthelinks.com /ch/Chemical_element.html   (387 words)

 Chemical element - Simple English Wikipedia
For example, all atoms with 6 protons in their nuclei are of the chemical element carbon, and all atoms with 92 protons in their nuclei are of the element uranium.
Chemical elements are commonly arranged in the periodic table.
Atoms of the same element, whose nuclei contain a different number of neutrons, are said to be different isotopes of the element.
simple.wikipedia.org /wiki/Chemical_element   (331 words)

 element. The Columbia Encyclopedia, Sixth Edition. 2001-05
Chemical properties are usually observed in the course of a chemical reaction, while physical properties are observed by examining a sample of the pure element.
The chemical properties of an element are due to the distribution of electrons around the atom’s nucleus, particularly the outer, or valence, electrons; it is these electrons that are involved in chemical reactions.
Elements with very similar chemical properties are often referred to as families; some families of elements include the halogens, the inert gases, and the alkali metals.
www.bartleby.com /65/el/element.html   (2007 words)

 Element, Chemical - Natural and synthetic elements, Classifying elements, Properties of the elements
Synthetic elements are usually produced in particle accelerators (devices used to increase the velocity of subatomic particles such as electrons and protons) or nuclear reactors (devices used to control the energy released by nuclear reactions).
The chemical symbol of an element is a letter or pair of letters that stands for some given amount of the element, for example, for one atom of the element.
Chemical elements can be fully identified, therefore, by any one of three characteristics: their name, their chemical symbol, or their atomic number.
www.scienceclarified.com /El-Ex/Element-Chemical.html   (1682 words)

 Chemical substance - Wikipedia, the free encyclopedia
A chemical element is a substance that cannot be decomposed or transformed into different substances by ordinary chemical methods.
A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in definite proportions.
A molecule is the smallest particle of an element or compound that retains the chemical characteristics of the element or compound.
en.wikipedia.org /wiki/Chemical   (245 words)

 NationMaster - Encyclopedia: Chemical element   (Site not responding. Last check: 2007-11-05)
A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions.
The atomic mass of a chemical element (also known as the relative atomic mass or average atomic mass or atomic weight) is the average atomic mass of all the chemical elements isotopes as found in a particular environment, weighted by isotopic abundance.
The periodic table of the chemical elements is a tabular method of displaying the chemical elements, first devised in 1789 by Antoine Lavoisier containing 33 elements, updated by Johann Dobereiner in 1817,John Newlands in 1863, Lothar Meyer in 1864 then redesigned as the modern table Known today in1869 by...
www.nationmaster.com /encyclopedia/Chemical-element   (3360 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)

 Chemical Glossary   (Site not responding. Last check: 2007-11-05)
is the smallest particle of a chemical element.
An element whose electrons are loosely held (first and second columns of chart) surrenders its outer electron(s) to an element with high ionization energy (that therefore has a high electron affinity).
Elements from opposite sides of the chart have very different ionization energies, so that one atom is strong enough to rip off electrons from the other.
www.petrik.com /PUBLIC/library/misc/chemical_glossary.htm   (1790 words)

 Chemical element Definition / Chemical element Research   (Site not responding. Last check: 2007-11-05)
A chemical element, often named simply element, is a substance that cannot be divided or changed into different substances by ordinary chemical methods.
chemical element is a substance which cannot be divided into smaller chemical parts.
Chemical element is a type of matter of which elementary matter is composed.
www.elresearch.com /Chemical_element   (346 words)

 Chemical element
The atomic mass of an element, A, is measured in atomic mass units (amu) and is roughly equal to the sum of the protons and neutrons in the nucleus of an atom of the element.
All man-made elements are radioactive with short half-lives so that any that were present at the formation of Earth have long since decayed.
The official names of the chemical elements are decided by the International Union of Pure and Applied Chemistry, which generally adopts the name chosen by the discoverer.
en.mcfly.org /Chemical_element   (556 words)

 Chemical element Summary
A chemical element is a substance that cannot be changed, broken down, or decomposed by ordinary chemical or physical methods into a simpler form.
A chemical element is composed of atoms, identical and unique for every element, that vary only in their mi...
Elements are substances that cannot be chemically broken into two or more pure substances.
www.bookrags.com /Chemical_element   (379 words)

 Formula, Chemical | World of Chemistry
The chemical formula of an ionic compound is simply the whole number ratio of the positive to negative ions encountered in the compound.
The chemical formula of an ionic compound is determined by knowing what elements are present, the valency of the elements, and the charge on the ions.
When working out the chemical formula it is convenient to put parentheses around the polyatomic ion to ensure that only the number of polyatomic ions is altered and not the number of the constituent atoms as this would give an entirely different compound.
www.bookrags.com /research/formula-chemical-woc   (1138 words)

 Reference.com/Encyclopedia/Chemical element
The smallest particle of such an element is an atom, which consists of electrons centered on a nucleus of protons and neutrons.
A number of elements are radioactive and in undergoing radioactive decay transmute into a different element.
A pure element can exist as monatomic units or as diatomic or polyatomic units comprising the same kind of atoms.
www.reference.com /browse/wiki/Chemical_element   (1121 words)

 Chemical element No. 110 finally gets a name -- darmstadtium
The decision on a name for chemical element No. 110 will mean instant obsolescence for current versions of the Periodic Table of the Elements, the charts that hang in chemistry classrooms and appear in textbooks around the world.
Elements are the basic chemical substances that make up everything in the universe -- from water, food, genes, and people to the glowing gasses in distant stars.
Element 110 was discovered in 1994 by scientists at the Laboratory for Heavy Ion Research, known as GSI, in Darmstadt, Germany.
www.post-gazette.com /healthscience/20030506element0506p4.asp   (471 words)

 The Chemical Elements
Elements with atomic numbers 101 and onwards are known as the transfermium elements.
They are also known as heavy elements because their atoms have very large masses compared with atoms of hydrogen, the lightest of all elements.
Elements 110 and 111 were discovered by the same group of scientists in 1994.
www.factmonster.com /ipka/A0772967.html   (418 words)

 Periodic Table of Elements: Terminology
Atomic Weight: The atomic weight of an element is the average relative weight of an element referred to Carbon 12 as the standard.
Atomic Number: It is an experimentally determined number characteristicof a chemical element that represents the number of protons in the nucleus which in a neutral atom equals the number of electrons outside the nucleus.
Oxidation State: The state of an element in a compound with respect to the number of electrons it has lost or gained, expressed as a positive or negative number indicating the ionic charge of an atom and equal to its valence.
www.corrosionsource.com /handbook/periodic/perd_term.htm   (369 words)

 element - Wiktionary
(chemistry) Any one of the simplest chemical substances that cannot be decomposed in a chemical reaction or by any chemical means and made up of atoms all having the same number of protons.
One of the four basic building blocks of matter in theories of ancient philosophers and alchemists: water, earth, fire, and air.
A component in electrical equipment, often in the form of a coil, having a high resistance, thereby generating heat when a current is passed through it.
en.wiktionary.org /wiki/element   (297 words)

 Chemical Element Iron Update - Chemical Element Iron News   (Site not responding. Last check: 2007-11-05)
Iron is a relatively abundant element in the universe.
Iron is a chemical element in the periodic table that has the symbol fe and atomic number 26.
Names were kept in most countries the official names of the chemical elements both ancient and to iupac, the full name of an element is not capitalized, even if.
www.irons-and-ironing.info /chemical-element-iron.html   (1179 words)

 SDV Nuclear Glossary   (Site not responding. Last check: 2007-11-05)
The set of chemical elements that form group IA in the periodic chart.
Elements with atomic numbers 58 through 71 (Z=57-71), the elements that follow lanthanum in the periodic chart.
The set of chemical elements that form a sort of boundary in the periodic chart between the metals and non-metals.
glossary.dataenabled.com /sdvglossary_elements.html   (4482 words)

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