In physics and chemistry , monatomic is a combination of the words mono and atomic, and means single atom . It is usually applied to gas es a monatomic gas is one in which atoms are not bound to each other. At standard temperature and pressure STP , all of the noble gas es are monatomic. These are helium , neon , argon , krypton , xenon and radon . The heavier noble gases can form compounds, but the lighter ones are unreactive. All elements will be monatomic in the gas phase at sufficiently high temperatures. The only mode of motion of a monatomic gas is translation electronic excitation is not important at room temperature . Thus in an adiabatic process , monatomic gases have an idealised Heat capacity ratio factor C sub p sub C sub v sub of 5 3, as opposed to 7 5 for ideal diatomic gases where rotation but not vibration at room temperature also contributes. Also, for ideal monatomic gases the molar heat capacity at constant pressure C sub p sub is 5 2 R 20.8 J&thinsp K sup 1 sup &thinsp mol sup 1 sup 4.97 Calorie cal &thinsp K sup 1 sup &thinsp mol sup 1 sup the molar heat capacity at constant volume C sub v sub is 3 2 R 12.5 J&thinsp K sup 1 sup &thinsp mol sup 1 sup 2.98 cal&thinsp K sup 1 sup &thinsp mol sup 1 sup where R is the gas constant . Category Gases chemistry stub ca Monoat mic es Monoat mico ja pl Monatomic tr Monatomik ... more details
Unreferenced date December 2009 A monatomic ion is an ion consisting of one or more atoms of a single element unlike a polyatomic ion , which consists of more than one element in one ion . For example calcium carbonate consists of the monatomic ion Ca sup 2 sup and the polyatomic ion CO sub 3 sub sup 2 sup . A type I binary ionic compound contains a metal cation that forms only one type of ion. A type II ionic compound contains a metal that forms more than one type of ion, i.e., ions with different electric charge charges . class wikitable colspan 2 Common type I Ion cations Hydrogen H sup sup Lithium Li sup sup Sodium Na sup sup Potassium K sup sup Rubidium Rb sup sup Cesium Cs sup sup Beryllium Be sup 2 sup Magnesium Mg sup 2 sup Calcium Ca sup 2 sup Strontium Sr sup 2 sup Barium Ba sup 2 sup Aluminum Al sup 3 sup Silver Ag sup sup Zinc Zn sup 2 sup class wikitable colspan 3 Common type II Ion cations iron II Fe sup 2 sup ferrous copper II Cu sup 2 sup cupric copper I Cu sup sup cuprous class wikitable colspan 2 Common Ion anions hydride H sup sup fluoride F sup sup chloride Cl sup sup bromide Br sup sup iodide I sup sup oxide O sup 2 sup sulfide S sup 2 sup nitride N sup 3 sup phosphide P sup 3 sup See also monatomic polyatomic ion DEFAULTSORT Monatomic Ion Category Ions el es Ion monoat mico ar ... more details
Gram atomic mass is the mass , in gram s, of one mole unit mole of atom s in a monatomic chemical element . It is numerically equal to the relative atomic mass or atomic weight in unified atomic mass unit s. chem stub Category Stoichiometry Category Mass sr ... more details
Tetrode can refer to Tetrode , an electronic device with four active electrodes, such as a vacuum tube Beam tetrode Tetrode biology , an electrode used in biology to sample neural signals Tetrode transistor , a transistor with four active terminals Sackur Tetrode equation , an expression for the entropy of a monatomic classical ideal gas Hugo Tetrode , a Dutch physicist 1895 1931 Willem Danielsz van Tetrode , a Dutch sculptor ca. 1530 ca. 1587 disamb ... more details
Unreferenced date December 2009 In semiconductor manufacturing plasma ashing is the process of removing the photoresist from an Etching microfabrication etched wafer. Using a Plasma physics plasma source, a monatomic reactive species is generated. Oxygen or fluorine are the most common reactive species. The reactive species combines with the photoresist to form ash which is removed with a vacuum pump . Typically, monatomic single atom oxygen plasma is created by exposing oxygen gas O sub 2 sub to non ionizing radiation . This process is done under vacuum in order to create a plasma. As the plasma is formed, many free radical s are created which could damage the wafer. Newer, smaller circuitry is increasingly susceptible to these particles. Originally, plasma was generated in the process chamber, but as the need to get rid of free radicals has increased, many machines now use a downstream plasma configuration, where plasma is formed remotely and the desired particles are channeled to the wafer. This allows electrically charged particles time to recombine before they reach the wafer surface, and prevents damage to the wafer surface. Two forms of plasma ashing are typically performed on wafers. High temp ashing, or stripping, is performed to remove as much photo resist as possible, while the descum process is used to remove residual photo resist in trenches. The main difference between the two processes is the temperature the wafer is exposed to while in an ashing chamber. Monatomic oxygen is electrically neutral and although it does recombine during the channeling, it does so at a slower rate than the positively or negatively charged free radicals, which attract one another. Effectively, this means that when all of the free radicals have recombined, there is still a portion of the active species available for process. Because a large portion of the active species is lost to recombination, process times may take longer. To some extent, these longer process times can be ... more details
In chemistry , homology refers to the appearance of homologues. A homologue also spelled as homolog is a chemical compound compound belonging to a series of compounds differing from each other by a repeating unit, such as a methylene methylene group , a peptide residue, etcetera. ref name iupac http www.chem.qmul.ac.uk iupac medchem ah.html h5 Glossary of Terms Used in Medicinal Chemistry IUPAC Recommendations 1998 ref A homolog is a special case of an analog chemistry analog . Examples are alkane s and compounds with alkyl sidechain s of different length the repeating unit being a methylene group CH sub 2 sub . On the periodic table , homologous elements share many chemical properties and appear in the same group column of the table. For example, all noble gases are colorless, monatomic gases with very low reactivity. These similarities are due to similar structure in their Electron shell outer shells of valence electrons . Homology in medicine refers to being from the same family. For example, the gastrointestinal tract hormone gastrin is homologous to cholecystokinin CCK , meaning they are from the same family of hormones. See also Homologous series Analog chemistry Analog Congener Chemistry Congener Structure activity relationship References references Category Chemical nomenclature ja lv Homologs zh ... more details
Citations missing article date September 2009 The Sackur Tetrode equation is an expression for the entropy of a monatomic classical ideal gas which incorporates quantum considerations which give a more detailed description of its regime of validity. The Sackur Tetrode equation is named for Hugo Martin Tetrode 1895 1931 and Otto Sackur 1880 1914 , who developed it independently as a solution of Boltzmann s gas statistics and entropy equations, at about the same time in 1912. The Sackur Tetrode equation is written math S k N ln left left frac VN right left frac UN right frac 32 right frac 32 kN left frac 53 ln frac 4 pi m 3h 2 right math where V is the volume of the gas, N is the number of particles in the gas, U is the internal energy of the gas, k is Boltzmann s constant , m is the mass of a gas particle, h is Planck s constant and ln is the natural logarithm . See Gibbs paradox for a derivation of the Sackur Tetrode equation. See also the ideal gas article for the constraints placed upon the entropy of an ideal gas by thermodynamics alone. The Sackur Tetrode equation can also be conveniently expressed in terms of the thermal wavelength math Lambda math . Using the classical ideal gas relationship U 3 2 NkT for a monatomic gas gives math frac S kN ln left frac V N Lambda 3 right frac 5 2 math Note that the assumption was made that the gas is in the classical regime, and is described by Maxwell Boltzmann statistics with correct counting . From the definition of the Thermal de Broglie wavelength thermal wavelength , this means the Sackur Tetrode equation is only valid for math frac V N Lambda 3 gg 1. math and in fact, the entropy predicted by the Sackur Tetrode equation approaches negative infinity as the temperature approaches zero. Sackur Tetrode constant The Sackur Tetrode constant , written S sub 0 sub R , is equal to S kN evaluated at a temperature of T 1 kelvin , at Standard state standard pressure 100 kPa or 101.325 kPa, to be specified , f ... more details
The Charged Aerosol Release Experiment also known as CARE , is a project run by NASA which will use a rocket to release of dust in the upper atmosphere to form a dusty plasma in space. ref cite web url http adsabs.harvard.edu abs 2008cosp...37..261B title The Charged Aerosol Release Experiment CARE Program coauthors Bernhardt, Paul Scales, Wayne Sternovsky, Zoltan Kelley, Michael Hysell, David Holzworth, Robert date 37th COSPAR Scientific Assembly. Held 13 20 July 2008, in Montr al, Canada., p.261 publisher Astrophysics Data System accessdate 2009 09 16 ref NASA plans to trigger cloud formation around the rocket s exhaust particles. ref cite web url http www.weaselzippers.net blog 2009 09 nasas charged aerosol release experiment care plans to make clouds tonight .html title NASA s Charged Aerosol Release Experiment CARE , Plans To Make Clouds Tonight . . . date September 15, 2009 publisher weaselzippers.net accessdate 2009 09 16 ref The clouds thus generated are intended to simulate naturally occurring phenomena called noctilucent clouds , which are the highest clouds in the atmosphere. The CARE experiment is intended to create an artificial dust layer at the boundary of space in a controlled sense, in order to allow scientists to study different aspects of it, the turbulence generated on the inside, the distribution of dust particles and such. ref cite news url http www.msnbc.msn.com id 32845270 ns technology and science space title NASA rocket aims to create artificial clouds last Moskowitz first Clara date updated 2 37 p.m. ET Sept. 16, 2009 publisher Msnbc accessdate 2009 09 16 ref The dust cloud is generated using the Nihka motor dust generator. The dust cloud is composed of aluminum oxide , carbon monoxide , hydrogen chloride , water , and nitrogen , as well as smaller amounts of carbon dioxide , hydrogen , monatomic chlorine , and monatomic hydrogen. ref cite web url http wpdp.colorado.edu Files Presentations BERNHARDT.pdf title Update on CARE last Bernhart f ... more details
in a factor of about 1000 loss in volumetric heat capacity. Monatomic gas heat capacities ... of the potential degrees of freedom per atom for storing energy in a monatomic gas, as compared with regard to an ideal solid. There is some difference in the heat capacity of monatomic vs. polyatomic ... more details
Unreferenced stub auto yes date December 2009 The enthalpy of atomization also atomisation in British spelling is the enthalpy change that accompanies the total separation of all atoms in a chemical substance either a chemical element or a chemical compound . This is often represented by the symbol sub at sub H sup s o s sup or H sub a sub sup s o s sup . The associated standard enthalpy is known as the Standard enthalpy of atomization , sub at sub H sup s o s sup Joule kJ &thinsp mole unit mol sup 1 sup , at 298.15 Kelvin K or 25 degrees celsius and 101.3 Pascal unit kPa . The enthalpy change of atomization of gaseous water molecule H sub 2 sub O is, for example, the sum of the HO H and H O bond standard enthalpy change of dissociation dissociation enthalpies . The enthalpy of atomization of an elemental solid is exactly the same as the enthalpy of sublimation for any elemental solid that becomes a monatomic gas upon evaporation . There is a difference between a solid converting to a gas, and a diatomic gaseous element converting to gaseous atoms. The standard enthalpy change is based purely on the production of one mole of gaseous atoms. Standard enthalpy of atomization is the enthalpy change when 1 mol of atoms in the gas phase is formed from its element in its defined physical state under standard conditions 298.15K, 1 atm . All bonds in the compound are broken in atomization and none are formed, so enthalpies of atomization are always positive. DEFAULTSORT Enthalpy Change Of Atomization Category Enthalpy Chem stub ru ... more details
Infobox journal title Physics and Chemistry of Liquids cover File CoverIssuePhysicsandChemistryofLiquids.jpg discipline Chemistry , physics abbreviation Phys. Chem. Liq. impact 0.580 impact year 2009 editor N. H. March, G. G. N. Angilella website http www.tandf.co.uk journals titles 00319104.html publisher Taylor & Francis Taylor and Francis country United Kingdom history 1968 present frequency bimonthly formernames ISSN 0031 9104 eISSN 1029 0451 CODEN PCLQAC LCCN OCLC 50516984 Portal Chemistry Portal Physics Physics and Chemistry of Liquids is a peer review peer reviewed scientific journal that publishes experiment al and Scientific theory theoretical research articles focussed on the science of the liquid liquid state . The editor in chief editors in chief of Physics and Chemistry of Liquids are N. H. March and G. G. N. Angilella. According to the Journal Citation Reports , the journal has a 2009 impact factor of 0.580. ref Journal Citation Reports , 2010 ref Scope The journal s scope includes all types of liquids, from monatomic liquid s and their mixture s, through charged liquids to molecular liquids. Abstracting and indexing Physics and Chemistry of Liquids is abstracted and indexed in the following databases GEOBASE database GEOBASE Chemical Abstracts Service Chemical Abstracts Service CASSI PubMed MEDLINE Science Citation Index Web of Science References references External links Official http www.tandf.co.uk journals titles 00319104.html Category Chemistry journals Category Physics journals Category Publications established in 1968 Category English language journals Category Bimonthly journals Category Taylor & Francis academic journals ... more details
A hydrogen purifier is a device to purify hydrogen if hydrogen production is done from hydrocarbon sources, the ultra high purified hydrogen is needed for applications like Proton exchange membrane fuel cell PEM fuel cell s . Different methods are used but the most promising technique for removing unwanted contaminants uses dense thin metal membrane purifiers which are compact, relatively inexpensive and simple to use. ref http www.hydrogen.bham.ac.uk h2purify.htm Hydrogen purification membranes ref Palladium membrane hydrogen purifiers The palladium membrane is typically a metallic tube of a palladium and silver alloy material possessing the unique property of allowing only monatomic hydrogen to pass through its crystal lattice when it is heated above 300 C. ref http www.jmgpt.com Outside In vs. Inside Out Write Upnew.pdf Palladium membrane ref Pressure swing adsorption Pressure swing adsorption is used for the removal of carbon dioxide CO sub 2 sub as the final step in the large scale commercial synthesis of hydrogen . It can also remove methane , carbon monoxide , nitrogen , moisture and in some cases, argon , from hydrogen. Catalytic recombination or deoxygenation purifier Catalytic recombination or deoxygenation is used to removed oxygen O sub 2 sub impurity. The process is also known as a deoxo process. The oxygen reacts with the hydrogen to form water vapor, which can then be removed by a dryer if necessary. The catalysts that are used are based on platinum group metals PGM . A typical system could handle up to 3 O2 in H2 in the feed, and reduce the O2 content to less than 1ppm. ref http www.scribd.com doc 7201923 Solar Hydrogen 45 Home Power 67 October November 1998 ref Applications Hydrogen purifiers are used in metalorganic vapour phase epitaxy reactors for LED production. ref http www.sciencedirect.com science? ob ArticleURL& udi B6VM5 4KMG63S 1S& user 10& rdoc 1& fmt & orig search& sort d& docanchor &view c& searchStrId 1080053670& rerunOrigin google& ac ... more details
Unreferenced date December 2008 Orphan date December 2008 In astrophysics , what is referred to as entropy is actually the adiabatic invariant adiabatic constant derived as follows. Using the first law of thermodynamics for a quasistatic process quasi static , infinitesimal process for a hydrostatics hydrostatic system math dQ dU dW. , math For an ideal gas in this special case, the internal energy , U, is only a function of the temperature T therefore the partial derivative of heat capacity with respect to T is identically the same as the full derivative, yielding through some manipulation math dQ C V dT P ,dV. math Further manipulation using the differential version of the ideal gas law , the previous equation, and assuming constant pressure, one finds math dQ C P dT V ,dP. math For an adiabatic process math dQ 0 , math and recalling math gamma frac C P C V , math , one finds math frac V ,dP C P dT P ,dV C V dT math math frac dP P frac dV V gamma. math One can solve this simple differential equation to find math PV gamma text constant K , math This equation is known as an expression for the adiabatic constant, K, also called the adiabat. From the ideal gas equation one also knows math P frac rho k B T mu m H , math where math k B , math is Boltzmann s constant . Substituting this into the above equation along with math V grams rho , math and math gamma 5 3 , math for an ideal monatomic gas one finds math K frac k B T mu m H rho 2 3 , math where math mu , math is the mean molecular weight of the gas or plasma physics plasma and math m H , math is the mass of the Hydrogen atom , which is extremely close to the mass of the proton , math m p , math , the quantity more often used in astrophysical theory of galaxy cluster s. This is what astrophysicists refer to as entropy and has units of keV cm sup 2 sup . This quantity relates to the thermodynamic entropy as math S k B ln Omega S 0 , math where math Omega , math , the density of states in statistical theory, takes on ... more details
directly from the knowledge of the final and initial equilibrium states. For an ideal monatomic ... is also valid if the gas is not monatomic, as the volume dependence of an ideal gas in the dilute ... of freedom is the same as for a monatomic gas. One can also evaluate the entropy change using purely ... more details
in monatomic substances, and translations and rotations of polyatomic molecules in gases. Additionally ... from monatomic gases are not fixed constants and vary somewhat depending on temperature. Accordingly ... physics and chemistry Molecules are quite different from the monatomic gases like helium and argon . With monatomic gases, thermal energy comprises only translational motions. Translational motions ... are available for any individual atom, whether it is free, as a monatomic molecule, or bound into a polyatomic ... on their axes is essentially zero in monatomic gases, because the energy spacing of the associated ... degree of freedom as well, since such rotation is similar to rotation of monatomic atoms, and so ... molar, basis does not exceed the heat capacity of monatomic gases, unless vibrational modes are brought ... energy in intra atomic bonds in a molecule, which are not available to atoms in monatomic gases. Up ... as in a monatomic gas, by this mechanism of storing energy in the potentials of interatomic bonds. This gives many solids about twice the atom molar heat capacity of monatomic gases, at the highest ... capacity that is between that of monatomic gases frac 3 2 R per mole, where R is the ideal gas constant ... that of monatomic gases, on a per mole of atoms basis, it is five sixths that of a monatomic gas ... for atoms of a monatomic gas. Thus, this degree of freedom does not act to store heat, and does ... less than for a monatomic gas, so long as the temperature remains low enough that no vibrational ... of bond vibration, the heat capacity per volume or mole of molecules approaches seven thirds that of monatomic gases, or seven sixths of monatomic, on a mole of atoms basis. This is now a higher heat capacity per atom than the monatomic figure, because the vibrational mode enables an extra degree of potential energy freedom per pair of atoms, which monatomic gases cannot possess. ref The sup ... 1 sup vs. the monatomic gases which equal 12.4717 J mol sup 1 sup K sup 1 sup . Citations ... more details
Two or more molecular entity molecular entities atom s, molecule s, ion s are described as being isoelectronic with each other if they have the same number of electrons ref http www.iun.edu cpanhd C101webnotes chemical bond isoelectronic.html Isoelectronic Configurations iun.edu ref or a similar electron configuration ref http www.thefreedictionary.com isoelectronic Isoelectronic thefreedictionary.com ref and the same structure number and connectivity of atoms , regardless of the nature of the elements involved. The term valence isoelectronic is used when these molecular entities have the same number of valence electron s or a similar electron configuration, but may have a different number of atoms or a different bonding. ref Advances in Organonmetallic chemistry. F.G.A. Stone page 190 http books.google.co.uk books?id e6R4oMRDhvsC&lpg PP1&pg PA190 v onepage&q &f false google books link ref The statement These compounds or molecules are isoelectronic is not just an implemetation of the above definition. It has significance by fact that calculations on molecules and electron density, and therefore capability of reaction, have been performed on quite a lot of common substances. By identifying a new, rare or odd compound as being isoelectronic with an already known one offers clues to possible properties and reactions. Examples The nitrogen N atom and the oxygen O sup sup radical chemistry radical ion are isoelectronic because each has 5 electrons in the outer electronic shell. Similarly, the cation s potassium K sup sup , calcium Ca sup 2 sup , and scandium Sc sup 3 sup , the anion s chlorine Cl sup &minus sup , sulfur S sup 2&minus sup , and phosphorus P sup 3&minus sup are all isoelectronic with the argon Ar atom. In such monatomic cases, there is a clear trend in the sizes of such species, with atomic radius decreasing as charge chemistry charge increases. Carbon monoxide CO , N sub 2 sub and Nitrosonium NO sup sup are isoelectronic because each have 2 nuclei and 10 ... more details
Image Sig06 023.jpg 200px thumb right Photoevaporation occurring to a protoplanetary disk due to the presence of a nearby O type star. Photoevaporation denotes the process when a planet is stripped of its atmosphere or parts of the atmosphere due to high energy photon s and other electromagnetic radiation . If a photon interacts with an atmospheric molecule, the molecule is accelerated and its temperature increased. If sufficient energy is provided, the molecule or atom may reach the escape velocity of the planet and evaporate into space. The lower the mass number of the gas, the higher the velocity obtained by interaction with a photon. Thus hydrogen is the gas which is most prone to photoevaporation. Photoevaporation with protoplanetary disks Protoplanetary disk s can be dispersed by stellar wind and heating due to incident electromagnetic radiation. The radiation interacts with matter and thus accelerates it outwards. This effect is only noticeable when there is sufficient radiation strength, such as coming from nearby O and B type stars or when the central protostar commences nuclear fusion . The disk is composed of gas and dust. The gas, consisting mostly of light elements such as hydrogen and helium , is mainly affected by the effect, causing the ratio between gas and dust to increase. Radiation from the central star excites particles in the accretion disk. The Gravitational radius math r g math of the disk is ref Liffman, 2003, http articles.adsabs.harvard.edu cgi bin nph iarticle query?2003PASA...20..337L& data type PDF HIGH& whole paper YES& type PRINTER& filetype .pdf The Gravitational Radius of an Irradiated Disk , Publications of the Astronomical Society of Australia, 20 4 337 339 ref math r g frac left gamma 1 right 2 gamma frac GM mu k B T approx 1.4 frac left M M odot right left T 10 4 rm K right rm AU , math where math gamma math is the ratio of specific heats 5 3 for a monatomic gas , math G math the universal gravitational constant , ma ... more details
gamma frac 5 3 math for monatomic gasses like the noble gas ses. The formulas for specific heats would reduce in these special cases Monatomic math c V frac 3 R 2 math and math c P frac 5 R 2 ... more details
Orphan date January 2011 PBB geneid 26002 DBH like monooxygenase protein 1 , also known as monooxygenase X , is an enzyme that in humans is encoded by the MOXD1 gene . ref name entrez cite web title Entrez Gene monooxygenase, DBH like 1 url http www.ncbi.nlm.nih.gov sites entrez?Db gene&Cmd ShowDetailView&TermToSearch 26002 accessdate ref ref name pmid9751809 cite journal author Chambers KJ, Tonkin LA, Chang E, Shelton DN, Linskens MH, Funk WD title Identification and cloning of a sequence homologue of dopamine beta hydroxylase journal Gene volume 218 issue 1 2 pages 111 20 year 1998 month September pmid 9751809 doi url issn ref DBH like 1 maintains many of the structural features of dopamine beta monooxygenase Dopamine beta hydroxylase DBH . ref name pmid11028916 cite journal author Prigge ST, Mains RE, Eipper BA, Amzel LM.. title New insights into copper monooxygenases and peptide amidation structure, mechanism and function. journal Cell Mol Life Sci. volume 57 issue 8 9 pages 1236 59 year 2000 month August pmid 11028916 ISSN 1420682X doi 10.1007 PL00000763 url ref Since Peptidylglycine alpha hydroxylating monooxygenase PHM EC 1.14.17.3 is homologous to dopamine beta monooxygenase DBM EC 1.14.17.1 ref name pmid2792366 cite journal author Southan C, Kruse LI title Sequence similarity between dopamine beta hydroxylase and peptide alpha amidating enzyme evidence for a conserved catalytic domain. journal FEBS Lett. volume 255 issue 1 pages 116 20 year 1989 month September pmid 2792366 doi 10.1016 0014 5793 89 81072 5 url ref this concerns a structural basis for a new family of Monatomic ion copper type II , significantly specific for ascorbate dependent monooxygenases ref name pmid2792366 based on the corresponding mouse homolog. ref name pmid9751809 The pathway of catecholamine synthesis is a possible catecholamine binding Copper in health Hereditary copper metabolic diseases metabolic copper ref name pmid15337741 cite journal author Xin X, Mains RE, Eipper BA.. titl ... more details
gases, such as xenon for monatomic gases the speed of sound is about 75 of the mean speed that molecules ..., and so both have an influence on speed of sound. In general, at the same molecular mass, monatomic ... 5 3 1.66... than diatomics do 7 5 1.4 . Thus, at the same molecular mass, the sound speed of a monatomic gas goes up by a factor of math c mathrm gas monatomic over c mathrm gas diatomic sqrt 5 3 over ... molecules monatomic molecules travel faster in a sound wave and transmit sound faster. Sound generally ... temperatures and vibrational heat capacity acts to increase the difference between sound speed in monatomic ... more details
Unreferenced date December 2009 Orphan date December 2009 Electrovalency is a measurement of the net electric charge of an ion and is used when balancing chemical reactions. Electrovalency is related to the concepts of electronegativity and valence electrons , and indicates the number of electrons necessary for an ion to have a balanced electric charge. Atoms that have an almost full or almost empty valence shell s tend to be very chemical reaction reactive . Atoms that are strongly electronegative as is the case with halogens often only have one or two missing electrons in their valence shell, and frequently chemical bond bond with other molecules or gain electrons to form anions . Atoms that are weakly electronegative such as alkali metals have relatively few valence electrons that can easily be lost to atoms that are strongly electronegative. As a result, weakly electronegative atoms tend to lose their electrons and form cations . The electrovalency of an element or compound is expressed as a charge. Atoms or molecules that have lost electrons have an electrovalency greater than zero and are known as cations. When an atom or molecule gains electrons, it is called an anion. When an atom or molecule has an electrovalency of zero, it has no net electric charge. When writing about an ion, the convention is to write the chemical formula followed by the electrovalency as a superscript, illustrated below p align center Silver Ag sup sup , Cobalt Co sup 2 sup , Iron Fe sup 3 sup , Cyanide CN sup sup , Carbonate CO sub 3 sub sup 2 sup , Phosphate PO sub 4 sub sup 3 sup . When an ion only contains a single atom it is called a monatomic ion , and when it contains more than one atom, it is called a polyatomic ion . On the above list, Ag sup sup would be a monatomic cation and PO sub 4 sub sup 3 sup would be a polyatomic anion. Electrovalency tables These tables show the charges of ions formed by common elements and compounds. These tables are used to determine the proportion ... more details
, dealt with the role of group theory in quantum dynamics in monatomic systems and comparisons of the nuclear .... f. Physik 47 , 1 1928 Carl Eckart The Application of Group theory to the Quantum Dynamics of Monatomic ... more details
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