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Encyclopedia > Molecular compound
3D (left and center) and 2D (right) representations of the terpenoid molecule atisane.
3D (left and center) and 2D (right) representations of the terpenoid molecule atisane.

In chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two atoms in a definite arrangement held together by strong chemical bonds.[1][2] In organic chemistry and biochemistry, the term molecule is used less strictly and also is applied to charged organic molecules and biomolecules. Image File history File links Please see the file description page for further information. ... In chemistry, a molecular compound, or covalent compound, is a big cock sucker who likes it in the anus. ... An example for the Molecule article based on Image:Atisane. ... An example for the Molecule article based on Image:Atisane. ... The space we live in is three-dimensional space. ... A 2D geometric model is a geometric model of an object as two-dimensional figure, usually on the Euclidean or Cartesian plane. ... The terpenoids, sometimes referred to as isoprenoids, are a large and diverse class of naturally occurring organic chemicals similar to terpenes, derived from five-carbon isoprene units assembled and modified in thousands of ways. ... It has been suggested that the central science be merged into this article or section. ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... Properties In chemistry and physics, an atom (Greek ἄτομος or átomos meaning indivisible) is the smallest particle still characterizing a chemical element. ... A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds. ... Organic chemistry is a specific discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting of primarily carbon and hydrogen, which may contain any number of other elements, including nitrogen, oxygen, halogens as well... Biochemistry is the study of the chemical processes and transformations in living organisms. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon and hydrogen; therefore, carbides, carbonates, carbon oxides and elementary carbon are not organic (see below for more on the definition controversy... ...


This definition has evolved as knowledge of the structure of molecules has increased. Earlier definitions were less precise defining molecules as the smallest particles of pure chemical substances that still retain their composition and chemical properties.[3] This definition often breaks down since many substances in ordinary experience, such as rocks, salts, and metals, are composed of atoms or ions, but are not made of molecules. This is a list of particles in particle physics, including currently known and hypothetical elementary particles, as well as the composite particles that can be built up from them. ... Water and steam are two different forms of the same chemical substance A chemical substance is any material with a definite chemical composition, no matter where it comes from. ... A chemical compound is a chemical substance of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. ... The rocky side of a mountain creek near Orosí, Costa Rica. ... For other uses, see Salt (disambiguation). ... Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily loses electrons to form positive ions (cations) and has metallic bonds between metal atoms. ... An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas colored yellow An ion is an atom or group of atoms which have lost or gained one or more electrons, making them negatively or positively charged. ...


In the kinetic theory of gases the term molecule is often used for any gaseous particle regardless of their composition.[4] According to this definition noble gases would also be considered molecules despite the fact that they are composed of a single non-bonded atom. Kinetic theory attempts to explain macroscopic properties of gases, such as pressure, temperature, or volume, by considering their molecular composition and motion. ... This article does not cite any references or sources. ... Neon, like all noble gases, has a full valence (outermost) electron shell. ...

Contents

History

Although the existence of molecules was accepted by many chemists since the early 19th century as a result of Dalton's laws of Definite and Multiple Proportions (1803-1808) and Avogadro's law (1811), there was some resistance among positivists and physicists such as Mach, Boltzmann, Maxwell, and Gibbs, who saw molecules merely as convenient mathematical constructs. The work of Perrin on Brownian motion (1911) is considered to be the final proof of the existence of molecules. In chemistry, the history of the molecule traces the origins of the concept or idea of the existence, in nature, of a bonded structure of two or more atoms, according to which the structures of the universe are built. ... John Dalton John Dalton (September 6, 1766 – July 27, 1844) was an English chemist and physicist, born at Eaglesfield, near Cockermouth in Cumberland. ... This article or section does not cite its references or sources. ... Logical positivism is a school of philosophy that combines empiricism—the idea that observational evidence is indispensable for knowledge of the world — with a version of rationalism—the idea that our knowledge includes a component that is not derived from observation. ... Ernst Mach Ernst Mach (February 18, 1838 – February 19, 1916) was an Austrian-Czech physicist and philosopher and is the namesake for the Mach number and the optical illusion known as Mach bands. ... Ludwig Eduard Boltzmann (Vienna, Austrian Empire, February 20, 1844 – Duino near Trieste, September 5, 1906) was an Austrian physicist famous for his founding contributions in the fields of statistical mechanics and statistical thermodynamics. ... James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish mathematician and theoretical physicist. ... Josiah Willard Gibbs (February 11, 1839 – April 28, 1903) was an American mathematical physicist who contributed much of the theoretical foundation that led to the development of chemical thermodynamics and was one of the founders of vector analysis. ... Jean Baptiste Perrin, generally known as Jean Perrin (Lille, September 30, 1870 – April 17, New York, 1942), was a French physicist. ... Year 1911 (MCMXI) was a common year starting on Sunday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Saturday of the 13-day-slower Julian calendar). ...


Overview

In a molecule, at least two atoms are joined by shared pairs of electrons in a covalent bond. It may consist of atoms of the same chemical element, as with oxygen (O2), or of different elements, as with water (H2O). Atoms and complexes connected by non-covalent bonds such as hydrogen bonds or ionic bonds are generally not considered single molecules. e- redirects here. ... Covalent bonding is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. ... The periodic table of the chemical elements A chemical element, or element for short, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... This article describes water from a scientific and technical perspective. ... An example of a quadruple hydrogen bond between a self-assembled dimer complex reported by Meijer and coworkers. ... Electron configurations of lithium and fluorine. ...


No typical molecule can be defined for ionic (salts) and covalent crystals (network solids) which are composed of repeating unit cells that extend either in a plane (such as in graphite) or three-dimensionally (such as in diamond or sodium chloride). A magnified crystal of salt In chemistry, salt is a term used for ionic compounds composed of positively charged cations and negatively charged anions, so that the product is neutral and without a net charge. ... In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... Two intersecting planes in three-dimensional space In mathematics, a plane is a two-dimensional manifold or surface that is perfectly flat. ... Graphite (named by Abraham Gottlob Werner in 1789 from the Greek γραφειν (graphein): to draw/write, for its use in pencils) is one of the allotropes of carbon. ... This article is about the gemstone. ... Jordanian and Israeli salt evaporation ponds at the south end of the Dead Sea Sodium chloride, also known as common salt, table salt, or halite, is a chemical compound with the formula NaCl. ...


The science of molecules is called molecular chemistry or molecular physics, depending on the focus. Molecular chemistry deals with the laws governing the interaction between molecules that results in the formation and breakage of chemical bonds, while molecular physics deals with the laws governing their structure and properties. In practice, however, this distinction is vague. In molecular sciences, a molecule consists of a stable system (bound state) comprising two or more atoms. Polyatomic ions may sometimes be usefully thought of as electrically charged molecules. The term unstable molecule is used for very reactive species, i.e., short-lived assemblies (resonances) of electrons and nuclei, such as radicals, molecular ions, Rydberg molecules, transition states, Van der Waals complexes, or systems of colliding atoms as in Bose-Einstein condensates. Molecular physics is the study of the physical properties of molecules and of the chemical bonds between atoms that bind them into molecules. ... A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds. ... In physics, a bound state is a composite of two or more building blocks (particles or bodies) that behaves as a single object. ... Properties In chemistry and physics, an atom (Greek ἄτομος or átomos meaning indivisible) is the smallest particle still characterizing a chemical element. ... An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas coloured yellow A polyatomic ion is a molecule that bears ionic groups, that is, a molecule with a charge. ... Reactivity refers to the rate at which a chemical substance tends to undergo a chemical reaction in time. ... This article is about resonance in physics. ... The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ... In chemistry, radicals (often referred to as free radicals) are atomic or molecular species with unpaired electrons on an otherwise open shell configuration. ... An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas colored yellow An ion is an atom or group of atoms which have lost or gained one or more electrons, making them negatively or positively charged. ... DIFFERENTIATE PARTICLES FROM NANOPARTICLE ... The transition state of a chemical reaction is a particular configuration along the reaction coordinate. ... Van der Waals bonding, also known as London force, instantaneous dipole effect, and induced dipole interaction, is an intermolecular force or interatomic force that causes an attraction between temporarily induced dipoles in nonpolar molecules and atoms. ... A Bose–Einstein condensate is a phase of matter formed by bosons cooled to temperatures very near to absolute zero (0 kelvins or -273. ...


Molecular size

Most molecules are far too small to be seen with the naked eye, but there are exceptions. DNA, a macromolecule, can reach macroscopic sizes, as can molecules of many polymers. The smallest neutral molecule is the diatomic hydrogen (H2), with an overall length of roughly twice the 74 picometres (0.74 Å) bond length. Molecules commonly used as building blocks for organic synthesis have a dimension of a few Å to several dozen Å. Single molecules cannot usually be observed by light (as noted above), but small molecules and even the outlines of individual atoms may be traced in some circumstances by use of an atomic force microscope. Some of the largest molecules are supermolecules. The structure of part of a DNA double helix Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living organisms. ... A macromolecule is a large molecule with a large molecular mass bonded covalently, but generally the use of the term is restricted to polymers and molecules which structurally include polymers. ... Macroscopic is commonly used to describe physical objects that are measurable and observable by the naked eye. ... A computer rendering of the Nitrogen Molecule, which is a diatomic molecule. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... One picometre is defined as 1x10-12 metres, in standard units. ... An angstrom, angström, or Ã¥ngström (symbol Ã…) is a unit of length. ... Topographic scan of a glass surface The atomic force microscope (AFM) is a very high-resolution type of scanning probe microscope, with demonstrated resolution of fractions of a nanometer, more than 1000 times better than the optical diffraction limit. ... A supermolecule sometimes called a supramolecule is a discrete complex of two or more molecules often macromolecules that are not covalently bonded. ...


Molecular formula

The empirical formula of a molecule is the simplest integer ratio of the chemical elements that constitute the compound. For example, in their pure forms, water is always composed of a 2:1 ratio of hydrogen to oxygen, and ethyl alcohol or ethanol is always composed of carbon, hydrogen, and oxygen in a 2:6:1 ratio. However, this does not determine the kind of molecule uniquely - dimethyl ether has the same ratio as ethanol, for instance. Molecules with the same atoms in different arrangements are called isomers. The empirical formula is often the same as the molecular formula but not always. For example the molecule acetylene has molecular formula C2H2, but the simplest integer ratio of elements is CH. The molecular formula reflects the exact number of atoms that compose a molecule. In chemistry, the empirical formula of a chemical compound is a simple expression of the relative number of each type of atom (called a chemical element) in it. ... The integers are commonly denoted by the above symbol. ... A ratio is a quantity that denotes the proportional amount or magnitude of one quantity relative to another. ... The periodic table of the chemical elements A chemical element, or element for short, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... Functional group of an alcohol molecule. ... Grain alcohol redirects here. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... Dimethyl ether, also known as methoxymethane, oxybismethane, methyl ether, wood ether, and DME, is a colorless gaseous ether with an ethereal odor. ... Properties In chemistry and physics, an atom (Greek ἄτομος or átomos meaning indivisible) is the smallest particle still characterizing a chemical element. ... In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of chemical bonds between atoms, but in which the atoms are arranged differently (analogous to a chemical anagram). ... Acetylene (systematic name: ethyne) is the simplest alkyne hydrocarbon, consisting of two hydrogen atoms and two carbon atoms connected by a triple bond. ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ...


The molecular mass can be calculated from the chemical formula and is expressed in conventional atomic mass units equal to 1/12th of the mass of a neutral carbon-12 (12C isotope) atom. For network solids, the term formula unit is used in stoichiometric calculations. The molecular mass (abbreviated Mr) of a substance, formerly also called molecular weight and abbreviated as MW, is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12). ... The unified atomic mass unit (u), or Dalton (Da), is a small unit of mass used to express atomic and molecular masses. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ... Isotopes are any of the several different forms of an element each having different atomic mass (mass number). ... A formula unit in chemistry is the empirical formula of an ionic or covalent network solid compound used as an independent entity for stoichiometric calculations. ... In chemistry, stoichiometry is the study of the combination of elements in chemical reactions. ...


Molecular geometry

Main article: Molecular geometry

Molecules have fixed equilibrium geometries—bond lengths and angles— about which they continuously oscillate through vibrational and rotational motions. A pure substance is composed of molecules with the same average geometrical structure. The chemical formula and the structure of a molecule are the two important factors that determine its properties, particularly its reactivity. Isomers share a chemical formula but normally have very different properties because of their different structures. Stereoisomers, a particular type of isomers, may have very similar physico-chemical properties and at the same time very different biochemical activities. Geometry of the water molecule Molecular geometry or molecular structure is the three dimensional arrangement of the atoms that constitute a molecule, inferred from the spectroscopic studies of the compound. ... A standard definition of mechanical equilibrium is: A system is in mechanical equilibrium when the sum of the forces, and torque, on each particle of the system is zero. ... In mathematics, an average or central tendency of a set (list) of data refers to a measure of the middle of the data set. ... Reactivity refers to the rate at which a chemical substance tends to undergo a chemical reaction in time. ... Stereoisomerism is the arrangement of atoms in molecules whose connectivity remains the same but their arrangement in space is different in each isomer. ... Biochemistry is the study of the chemical processes and transformations in living organisms. ...


Molecular spectroscopy

Main article: Spectroscopy

Molecular spectroscopy deals with the response (spectrum) of molecules interacting with probing signals of known energy (or frequency, according to Planck's formula). Scattering theory provides the theoretical background for spectroscopy. Extremely high resolution spectrogram of the Sun showing thousands of elemental absorption lines (fraunhofer lines) Spectroscopy is the study of the interaction between radiation (electromagnetic radiation, or light, as well as particle radiation) and matter. ... Familiar concepts associated with a frequency are colors, musical notes, radio/TV channels, and even the regular rotation of the earth. ... FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. ... A commemoration plaque for Max Planck on his discovery of Plancks constant, in front of Humboldt University, Berlin. ... Scattering theory is a branch of physics and especially of quantum mechanics whose aim is the study of scattering events. ...


The probing signal used in spectroscopy can be an electromagnetic wave or a beam of particles (electrons, positrons, etc.) The molecular response can consist of signal absorption (absorption spectroscopy), the emission of another signal (emission spectroscopy), fragmentation, or chemical changes. Electromagnetic radiation is a propagating wave in space with electric and magnetic components. ... In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not made up of smaller particles. ... e- redirects here. ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... Absorption spectroscopy refers to a wide range of techniques where one measures how much light of a particular wavelength (color) is absorbed by a sample. ... a Headline text hi today for the first time i fucked my 14 years neighbour she was very excited when she saw my dick thouh it was a bit thick and long but she gladly become agree to let me fuck her at my first stroke i broke her seal...


Spectroscopy is recognized as a powerful tool in investigating the microscopic properties of molecules, in particular their energy levels. In order to extract maximum microscopic information from experimental results, spectroscopy is often coupled with chemical computations. A microscope (Greek: micron = small and scopos = aim) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ... A quantum mechanical system can only be in certain states, so that only certain energy levels are possible. ... Computational chemistry is a branch of chemistry that uses the results of theoretical chemistry incorporated into efficient computer programs to calculate the structures and properties of molecules and solids, applying these programs to real chemical problems. ...


Theoretical aspects

The study of molecules by molecular physics and theoretical chemistry is largely based on quantum mechanics and is essential for the understanding of the chemical bond. The simplest molecules used as model systems since the early days of quantum chemistry are the hydrogen molecule and its cation, H2+. Among these two, the cation has the advantage of being a one-electron system, which means that the Schrödinger equation for the system can be solved more easily due to the lack of electron–electron repulsion. With the development of fast digital computers, approximate solutions for more complicated molecules became possible and are one of the main aspects of computational chemistry. Molecular physics is the study of the physical properties of molecules and of the chemical bonds between atoms that bind them into molecules. ... Theoretical chemistry is the use of reasoning to explain or predict chemical phenomena. ... Fig. ... A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds. ... Quantum chemistry is a branch of theoretical chemistry, which applies quantum mechanics and quantum field theory to address issues and problems in chemistry. ... The Hydrogen molecule consists of two Hydrogen atoms, in other words it is a diatomic molecule. ... For a non-technical introduction to the topic, please see Introduction to quantum mechanics. ... Computational chemistry is a branch of chemistry that uses the results of theoretical chemistry incorporated into efficient computer programs to calculate the structures and properties of molecules and solids, applying these programs to real chemical problems. ...


When trying to define rigorously whether an arrangement of atoms is "sufficiently stable" to be considered a molecule, IUPAC suggests that it "must correspond to a depression on the potential energy surface that is deep enough to confine at least one vibrational state".[1] This definition does not depend on the nature of the interaction between the atoms, but only on the strength of the interaction. In fact, it includes weakly-bound species that would not traditionally be considered molecules, such as the helium dimer, He2, which has one vibrational bound state but is so loosely bound that it is only likely to be observed at very low temperatures. A potential energy surface is generally used within the adiabatic or Born–Oppenheimer approximation in quantum mechanics and statistical mechanics to model chemical reactions and interactions in simple chemical and physical systems. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Standard atomic weight 4. ... Sucrose, or common table sugar, is composed of glucose and fructose. ... In physics, a bound state is a composite of two or more building blocks (particles or bodies) that behaves as a single object. ...


See also

Covalent bonding is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. ... Diatomic molecules are molecules formed of two atoms of the same element. ... In chemistry, the history of the molecule traces the origins of the concept or idea of the existence, in nature, of a bonded structure of two or more atoms, according to which the structures of the universe are built. ... Geometry of the water molecule Molecular geometry or molecular structure is the three dimensional arrangement of the atoms that constitute a molecule, inferred from the spectroscopic studies of the compound. ... The molecular Hamiltonian is an operator in quantum chemistry and atomic, molecular, and optical physics which describes the motions of electrons and nuclei in a polyatomic molecule. ... In chemistry, a molecular orbital is a region in which an electron may be found in a molecule. ... In chemistry, a nonpolar compound is one that does not have concentrations of positive or negative electric charge. ... A commonly-used example of a polar compound is water (H2O). ... The original list from this page has been split into the following three lists, as the number of compounds became too long. ... This is a list of molecules that have been detected in the interstellar medium, grouped by the number of component atoms. ...

References

  1. ^ a b International Union of Pure and Applied Chemistry (1994). "molecule". Compendium of Chemical Terminology Internet edition.
  2. ^ Pauling, Linus (1970). General Chemistry. New York: Dover Publications, Inc.. ISBN 0-486-65622-5. 
    Ebbin, Darrell, D. (1990). General Chemistry, 3th Ed.. Boston: Houghton Mifflin Co.. ISBN 0-395-43302-9. 
    Brown, T.L. (2003). Chemistry – the Central Science, 9th Ed.. New Jersey: Prentice Hall. ISBN 0-13-066997-0. 
    Chang, Raymond (1998). Chemistry, 6th Ed.. New York: McGraw Hill. ISBN 0-07-115221-0. 
    Zumdahl, Steven S. (1997). Chemistry, 4th ed.. Boston: Houghton Mifflin. ISBN 0-669-41794-7. 
  3. ^ Molecule Definition (Frostburg State University)
  4. ^ E.g. see [1]

IUPAC logo The International Union of Pure and Applied Chemistry (IUPAC) (Pronounced as eye-you-pack) is an international non-governmental organization established in 1919 devoted to the advancement of chemistry. ... Compendium of Chemical Terminology (ISBN 0-86542-684-8) is a book published by IUPAC containing internationally accepted definitions for terms in chemistry. ...

External links

  • Molecule of the Month - School of Chemistry, University of Bristol
  • Antibody Molecule - The National Health Museum
  • Data Book of Molecules - Home Page for Learning Environmental Chemistry


Hadrons: Baryons (list) | Mesons (list)

Baryons: Exotic baryons | Hyperons | Nucleons | Pentaquarks
Mesons: Exotic mesons | Glueballs | Kaons | Pions | Quarkonium | Tetraquarks
Atomic nuclei | Atoms (Periodic table (vertical)) | Molecules Thousands of particles explode from the collision point of two relativistic (100 GeV per ion) gold ions in the STAR detector of the Relativistic Heavy Ion Collider. ... Elementary particles An elementary particle is a particle with no measurable internal structure, that is, it is not a composite of other particles. ... A hadron, in particle physics, is a subatomic particle which experiences the nuclear force. ... Combinations of three u, d or s-quarks with a total spin of 3/2 form the so-called baryon decuplet. ... Baryon decuplet: Spin=3/2 Baryon octet: Spin=1/2 This is a list of baryons. ... Mesons of spin 1 form a nonet In particle physics, a meson is a strongly interacting boson, that is, it is a hadron with integral spin. ... A list of mesons. ... Ordinary baryons are bound states of 3 quarks. ... In particle physics, a hyperon is any subatomic particle which is a baryon (and hence a hadron and a fermion) with non-zero strangeness, but with zero charm and zero bottomness. ... In physics a nucleon is a collective name for two baryons: the neutron and the proton. ... A pentaquark is a subatomic particle consisting of a group of five quarks (compared to three quarks in normal baryons and two in mesons), or more specifically four quarks and one anti-quark. ... Identities and classification of possible tetraquark mesons. ... In particle physics, a glueball is a particle containing no valence quarks. ... In particle physics, Kaons (also called K-mesons and denoted K) are a group of four mesons distinguished by the fact that they carry a quantum number called strangeness. ... In particle physics, pion (short for pi meson) is the collective name for three subatomic particles: π0, π+ and π−. Pions are the lightest mesons and play an important role in explaining low-energy properties of the strong nuclear force. ... In high energy physics, a quarkonium (pl. ... A tetraquark is a subatomic particle composed of four quarks. ... The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ... Properties In chemistry and physics, an atom (Greek ἄτομος or átomos meaning indivisible) is the smallest particle still characterizing a chemical element. ... The alternative table is a standard periodic table rotated counterclockwise and then mirrored across the vertical axis, hence like in many writing systems, the lower groups are to the left and the number increases to the right. ...


Into Matter
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OrganismSystemOrganTissueCellOrganelleMoleculeAtomParticleQuark

  Results from FactBites:
 
compound. The Columbia Encyclopedia, Sixth Edition. 2001-05 (581 words)
Compounds are formed from simpler substances by chemical reaction.
It is composed of the silvery metal sodium and the greenish poisonous gas chlorine combined in the proportion of one atom of sodium to one atom of chlorine.
Sodium chloride is an ionic compound; it is made up of electrically charged ions that are present in fixed proportions and are arranged in a regular, geometric pattern (called crystalline structure) but are not grouped into molecules.
Chemical Composition (740 words)
The molecular weight of a substance is the sum of the atomic weight of the atoms in a molecule.
This means that molecular weight is the average mass of a molecule of a substance.
Compounds with different molecular formulas can have the same empirical formulas and such substances will have the same percentage composition.
  More results at FactBites »

 
 

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