1.3+Chemical+elements

​​​​Definition of chemical elements A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. The term is also used to refer to a pure chemical substance composed of atoms with the same number of protons. Common examples of elements are iron, copper, silver, gold, hydrogen, carbon, nitrogen, and oxygen. In total, 118 elements have been observed as of March 2010, of which 94 occur naturally on Earth. 80 elements have stable isotopes, namely all elements with atomic numbers 1 to 82, except elements 43 and 61 (technetium and promethium). Elements with atomic numbers 83 or higher (bismuth and above) are inherently unstable, and undergo radioactive decay. The elements from atomic number 83 to 94 have no stable nuclei, but are nevertheless found in nature, either surviving as remnants of the primordial stellar nucleosynthesis that produced the elements in the solar system, or else produced as short-lived daughter-isotopes through the natural decay of uranium and thorium chimical reactions

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History

Several old philosophies used a set of archetypal classical elements to explain patterns in nature. The term 'element' was originally used to refer to a state of matter(solid/earth, liquid/water, gas/air, and plasma/fire) or a phase of matter rather than the chemical elements of modern science. The Greek, Indian and Japanese traditions essentially had the same five elements: Air, Earth, Fire, Water and Aether. The term 'elements' was first used by the Greek philosopher Plato in about 360 BCE, in his dialogue Timaeus, which includes a discussion of the composition of inorganic and organic bodies and is a rudimentary treatise on chemistry. Plato assumed that the minute particle of each element corresponded to one of the regular polyhedra: tetrahedron (fire), octahedron (air), icosahedron (water), and cube (earth) Adding to the four elements of the Greek philosopher Empedocles, in about 350 BC, Aristotle also used the term "element" and conceived of a fifth element called "quintessence", which formed the heavens. Aristotle defined an element as:

Building on the theory in //circa// 790, Arab/Persian chemist and alchemist, Jabir ibn Hayyan postulated that metals were formed out of two elements: sulfur, ‘the stone that burns’, which characterized the principle of combustibility, and mercury, which contained the idealized principle of metallic properties. Shortly thereafter, this evolved into the Arabic concept of the three principles: sulfur giving flammability or combustion, mercury giving volatility and stability, and salt giving solidity.
 * Element** – one of those bodies into which other bodies can decompose, and that itself is not capable of being divided into other.

Periodic table take from [] ​​
 * || **1** || **2** || **3** || **4** || **5** || **6** || **7** || **8** || **9** || **10** || **11** || **12** || **13** || **14** || **15** || **16** || **17** || **18** ||
 * 1 || [|H] ||||||||||||||||||||||||||||||||  || [|He] ||
 * ^  || Hydrogen ||||||||||||||||||||||||||||||||^   || Helium ||
 * 2 || [|Li] || [|Be] ||||||||||||||||||||  || [|B] || [|C] || [|N] || [|O] || [|F] || [|Ne] ||
 * ^  || Lithium || Beryllium ||||||||||||||||||||^   || Boron || Carbon || Nitrogen || Oxygen || Fluorine || Neon ||
 * 3 || [|Na] || [|Mg] ||||||||||||||||||||^  || [|Al] || [|Si] || [|P] || [|S] || [|Cl] || [|Ar] ||
 * ^  || Sodium || Magnesium || Aluminum || Silicon || Phosphorus || Sulfur || Chlorine || Argon ||
 * 4 || [|K] || [|Ca] || [|Sc] || [|Ti] || [|V] || [|Cr] || [|Mn] || [|Fe] || [|Co] || [|Ni] || [|Cu] || [|Zn] || [|Ga] || [|Ge] || [|As] || [|Se] || [|Br] || [|Kr] ||
 * ^  || Potassium || Calcium || Scandium || Titanium || Vanadium || Chromium || Manganese || Iron || Cobalt || Nickel || Copper || Zinc || Gallium || Germanium || Arsenic || Selenium || Bromine || Krypton ||
 * 5 || [|Rb] || [|Sr] || [|Y] || [|Zr] || [|Nb] || [|Mo] || [|Tc] || [|Ru] || [|Rh] || [|Pd] || [|Ag] || [|Cd] || [|In] || [|Sn] || [|Sb] || [|Te] || [|I] || [|Xe] ||
 * ^  || Rubidium || Strontium || Yttrium || Zirconium || Niobium || Molybdenum || Technetium || Ruthenium || Rhodium || Palladium || Silver || Cadmium || Indium || Tin || Antimony || Tellurium || Iodine || Xenon ||
 * 6 || [|Cs] || [|Ba] || * || [|Hf] || [|Ta] || [|W] || [|Re] || [|Os] || [|Ir] || [|Pt] || [|Au] || [|Hg] || [|Tl] || [|Pb] || [|Bi] || [|Po] || [|At] || [|Rn] ||
 * ^  || Cesium || Barium ||   || Hafnium || Tantalum || Tungsten || Rhenium || Osmium || Iridium || Platinum || Gold || Mercury || Thallium || Lead || Bismuth || Polonium || Astatine || Radon ||
 * 7 || [|Fr] || [|Ra] ||  || [|Rf] || [|Db] || [|Sg] || [|Bh] || [|Hs] || [|Mt] || [|Uun] || [|Uuu] || [|Uub] ||||||||||||   ||
 * ^  || Francium || Radium ||   || Unnilquadium || Unnilpentium || Unnilhexium || Unnilseptium || Unniloctium || Unnilennium || Ununnilium || Unununium || Ununbium ||||||||||||^   ||
 * ^  || * || [|La] || [|Ce] || [|Pr] || [|Nd] || [|Pm] || [|Sm] || [|Eu] || [|Gd] || [|Tb] || [|Dy] || [|Ho] || [|Er] || [|Tm] || [|Yb] || [|Lu] ||
 * ^  ||   || Lanthanum || Cerium || Praseodymium || Neodymium || Promethium || Samarium || Europium || Gadolinium || Terbium || Dysprosium || Holmium || Erbium || Thulium || Ytterbium || Lutetium ||
 * ^  ||   || [|Ac] || [|Th] || [|Pa] || [|U] || [|Np] || [|Pu] || [|Am] || [|Cm] || [|Bk] || [|Cf] || [|Es] || [|Fm] || [|Md] || [|No] || [|Lr] ||
 * ^  ||   || Actinium || Thorium || Protactinium || Uranium || Neptunium || Plutonium || Americium || Curium || Berkelium || Californium || Einsteinium || Fermium || Mendelevium || Nobelium || Lawrencium ||
 * ~ **​Element Groups (Families)** ||
 * **Alkali Ear​th** || **Alkaline Earth** || **Transition Metals** ||
 * **Rare Earth** || **Other Metals** || **Metlloids** ||
 * **Non-Metals** || **Halogens** || **Noble Gases** ||
 * **Non-Metals** || **Halogens** || **Noble Gases** ||

= chemical elements =

A **chemical element** is a pure chemical substance consisting of one //type// of atom distinguished by its atomic number, which is the number of protons in its nucleus. The term is also used to refer to a pure chemical substance composed of atoms with the same number of protons. Common examples of elements are iron, copper, silver, gold, hydrogen, carbon, nitrogen, and oxygen. In total, 117 elements have been observed as of 2008, of which 94 occur naturally on Earth. 80 elements have stable isotopes, namely all elements with atomic numbers 1 to 82, except elements 43 and 61 (technetium and promethium). Elements with atomic numbers 83 or higher (bismuth and above) are inherently unstable, and undergo radioactive decay. The elements from atomic number 83 to 94 have no stable nuclei, but are nevertheless found in nature, either surviving as remnants of the primordial stellar nucleosynthesis that produced the elements in the solar system, or else produced as short-lived daughter-isotopes through the natural decay of uranium and thorium

= atomic number =

The atomic number of an element, //Z//, is equal to the number of protons that defines the element. For example, all carbon atoms contain 6 protons in their nucleus; so the atomic number "Z" of carbon is 6. Carbon atoms may have different numbers of neutrons, which are known as isotopes of the element. The number of protons in the atomic nucleus also determines its electric charge, which in turn determines the electrons of the atom in its non-ionized state. This in turn (by means of the Pauli exclusion principle) determines the atom's various chemical properties. So all carbon atoms, for example, ultimately have identical chemical properties because they all have the same number of protons in their nucleus, and therefore have the same atomic number. It is for this reason that atomic number rather than mass number (or atomic weight) is considered the identifying characteristic of an element.



[] pedro juan mejia aguilar

The chemical elements​ To know what is a chemical element we have to know first wath is an element, an element is a basic sustance that are pure and can be conbinated with other elements to form compounds, and those elements can not be descopound in an other simplier element. With those items we can told what is a chemical element, the chemical element are organized in the periodic table but in this unit we are no gone to talk about the periodi table, we are gone to talk about the chemical elements, the chemical elements can be semi metalic elements, no metalics, metalics, solid elements, liquid elements,radiactive elements, lanthinid elements and actinid elements, each one with his properties, an element is a sustance with the same class of atoms so the properties of the atoms are too the properties of the elements, the chemical elements are represented in the periodic table. the natural elements known until now are 118.

in the next video is explained the names of all the elements of the periodic table and a little about how we can find it. media type="youtube" key="0rJmILZ8Psc" height="332" width="447" the pages needed to this text was youtube,com an the other pages from images

all was mine textual production with the guide of the bokkportal de la ciencia 7 editorial norma Edwin Bedoya Cardona numero 10 7b march 17 of 2010 A chemical element can be defined in one of two ways: experimentally or theoretically. Experimentally, an element is any substance that cannot be broken down into any simpler substance

The experimental definition of an element can be explained by using a second definition: an element is a substance in which all atoms are of the same kind. If there were a way to look at each of the individual atoms in the bar of pure iron mentioned above, they would all be the same—all atoms of iron. In contrast, a chemical compound, such as iron oxide, always contains at least two different kinds of atoms, in this case, atoms of iron and atoms of oxygen.http://www.scienceclarified.com/El-Ex/Element-Chemical.html




 * a//toms// **

A chemical element is a type of matter, constituted by atoms of the same class. In his(her,your) simpler form it(he,she) possesses a certain number of protons in his(her,your) core(nucleus), making it belong(concern) to the only(unique) category classified with the atomic number, even if this one could show different atomic masses. It is an atom with the physical only(unique) characteristics, which by tradition are defined as that substance that cannot be separated into its elements(decomposed) by means of a chemical reaction, in simpler others. There do not exist two atoms of the same element with different characteristics and, in case these possess different mass, belong(concern) to the same element but in what is known as one of his(her,your) isotopes. Also it is important to differ between(among) a " chemical element " of a simple substance.

= = While various types of microscopes can reveal details at many levels of magnification, no microscope can produce images showing the detailed parts of single atoms. For understanding atoms at this level, we traditionally use models instead of actual images. The models presented in this investigation show a highly simplified view of atoms, but they serve the purpose of allowing us to examine the number of protons, neutrons, and electrons in common elements. []​​