Download 5-Appendix F.Pdf

Total Page:16

File Type:pdf, Size:1020Kb

Download 5-Appendix F.Pdf When and from where did Bohr receive When and where was Niels Bohr born? What religion did Bohr follow? his doctorate in physics? How did Niels Bohr hide Max von Laue’s When and for what did Bohr win a No- What famous WWII project did Bohr and James Franck’s gold Nobel medals bel Prize in physics? work on in the United States? from the Nazis? What was the content of Bohr’s “Open Where did Bohr go when the Nazis What element is named after Niels Letter to the United Nations” in June, occupied Denmark? Bohr? What number is it? 1950? How many papers did Niels Bohr What did Niels Bohr’s children do with When and where did Niels Bohr die? publish? their lives? What name did Niels Bohr take on What did Bohr found at Copenhagen How did Bohr participate in WWI? while living in the US during WWII? University in 1920? For what work did Bohr win a prize in Where and for whom was Bohr working Where and for whom was Bohr working 1908? in 1911? in 1912? October 7, 1885. Bohr was an atheist. 1911, Copenhagen University. Copenhagen, Denmark. Bohr dissolved them in acid, then precipitated the gold out after the war The Manhattan Project. 1922, for work on atomic structures and had the medals re-struck by the Nobel Foundation. His views on nuclear weapons, and his Number 107, bohrium desire for a development towards full Sweden, and then the UK. openness between nations. Of the six, four reached adulthood: Aage became a physicist, Hans Henrik became a physician, Erik a chemical November 18, 1962, in Copenhagen. At least 115. engineer, and Ernest a lawyer. Ernest also played field hockey for Denmark at the 1948 Summer Olympics. Bohr was named ‘Nicholas Baker’ for Niels Bohr played no part in WWI. The Institute of Theoretical Physics security purposes. Ernest Rutherford’s laboratory in Man- The Cavendish Laboratory (Cambridge, An investigation of surface tension by chester, UK. UK) under Sir J.J. Thomson. means of oscillating fluid jets. On what order of magnitude is the On what order of magnitude is the On what order of magnitude is the weight of a n electron? weight of a proton? weight of a neutron? If two atoms have the same number of What keeps the electrons of an atom What determines the atomic number of protons but a different number of neu- orbiting the nucleus of the atom? an element? trons, what are they called? What subatomic particle has a positive What subatomic particle has a negative What subatomic particle has a neutral charge? charge? charge? What subatomic particles are in the What happens in an ionic bond? What happens in a covalent bond? nucleus? What is an atomic radius, and what A proton’s mass is ______ times the What is Avogadro’s number? does it assume? mass of an electron. What is the nucleus of an atom held How many electrons can the first How many electrons can the second together by? energy shell hold? and third energy shells hold? 10-26 g 10-26 g 10-28 g Isotopes The number of protons. A Coulombic attraction A neutron An electron A proton An atom with ‘extra’ electrons gives Two atoms share electrons them to an atom that is ‘short’ of elec- Protons and neutrons trons The distance out to which an electron cloud extends beyond the nucleus. It 1836 6.022 x 1023 assumes that an atom exhibits spherical shape. Eight each Two Nuclear forces What atomic model was proposed in What did the Plum Pudding atomic What experiment disproved the Plum 1904 by J.J. Thompson? model look like? Pudding atomic model? What did the Rutherford atomic model In what year did Rutherford present his What Japanese scientist developed an look like? model? atomic model in 1904? What atomic model was developed in What atomic model replaced the When did Niels Bohr propose the 1902 but proposed in 1916 by Gilbert Rutherford model? atomic model since named after him? Lewis? What are the main points of the Bohr What atomic model is portrayed by this The Rutherford model is also know as model? game board? the _______ model. What were the significant shortcomings What element was Bohr’s model good How does Schrödinger’s equation de- of the planetary model? at representing? scribe an electron? How did Arnold Sommerfeld change the What is the current model of the atom? When was the nucleus discovered? Bohr model? The Geiger-Marsden gold foil experi- Negative electrons floating in a The Plum Pudding model ment. positively-charged soup A dense, positively-charged volume located in the center of the atom, Hantaro Nagaoka 1911 surrounded by a cloud of orbiting electrons. The cubical atom model, in which The Rutherford-Bohr model, also know electrons are located at the corners of a 1913 as the Bohr model cube in a nonpolar atom That electrons orbit the nucleus in certain orbits at discrete distances from Planetary The Bohr or the Rutherford model the nucleus, and that electrons can only gain and lose energy by jumping from one orbit to another. That electrons are charged particles, unlike planets orbiting the sun, and that Schrödinger’s equation describes an Hydrogen it could not explain the highly peaked electron as a wavefunction. emission and absorption spectra observed. The currently accepted atomic model is Sommerfeld added elliptical orbits 1917 the quantum-mechanical model. On what order of magnitude is the On what order of magnitude is the What is the electromagnetic spectrum? wavelength of radio waves? wavelength of microwaves? On what order of magnitude is the On what order of magnitude is the On what order of magnitude is the wavelength of infrared light? wavelength of visible light? wavelength of ultraviolet light? When was the first discovery of On what order of magnitude is the On what order of magnitude is the electromagnetic waves other than wavelength of x-rays? wavelength of gamma rays? light? Heinrich Hertz built a device in 1886. What do Maxwell’s equations predict? When were X-rays discovered? What did it do? Does red light have a larger or smaller What are gamma rays generated from? What generates X-rays? wavelength than violet light? What does terahertz radiation fall What electromagnetic radiation wave- between on the electromagnetic What type of ray does a PET scan use? lengths can the human eye detect? spectrum? The electromagnetic spectrum is the 10-2 m 103 m range of all possible frequencies of electromagnetic radiation. 10-8 m .05 x 10-6 m 10-5 m 1800 10-12 m 10-10 m An infinite number of frequencies of 1895 Generate and detect radio waves electromagnetic waves. X-rays are generated Gamma rays are the photons generated The wavelength or red light is larger by electronic transitions involving from nuclear decay or other subnuclear than that of violet light. highly energetic inner atomic electrons processes. Anything with a wavelength between Terahertz waves fall between infrared Gamma rays 380 and 760 nm and microwaves. What two elements did the Curies When was it discovered that radiation Who discovered radiation? discover? could cause injury? Who discovered the existence of the Who created the first artificial What series of elements on the periodic half-life of a radioactive element? radioactivity, and when did they do it? table are all radioactive? What is nuclear fission? What is nuclear fusion? What is an alpha particle? Who suffered the first recognized What is a beta particle? What does a Geiger counter detect? radiation burn? What characteristic must a material How many man-made isotopes are What is radioactive decay? have to be considered radioactive? radioactive? Very large nuclei tend to be unstable Who discovered the genetic effects of What is neutron emission? because of what? radiation? 1901 Polonium and radium Henri Becquerel Marie Curie’s daughter, Irene Joliot- Curie, and her husband, in 1934 The actinides Ernest Rutherford Nuclear fusion is a nuclear reaction in An alpha particle consists of two A nuclear reaction or decay in which which two or more atomic nuclei collide protons and two neutrons bound the nucleus of a particle splits into at very high speed and join to form a together. smaller particles new atomic nucleus A Geiger counter detects the emission Beta particles are high-energy, high- of nuclear radiation, including alpha Nikola Tesla speed electrons or positrons emitted by particles, beta particles, and gamma certain types of radioactive nuclei rays The process by which a nucleus of an The material must spontaneously emit All of them unstable atom loses energy by emitting ionizing radiation particles of ionizing radiation A type of radioactive decay of atoms containing excess neutrons, in which a Hermann Joseph Muller The repulsive forces between protons neutron is simply ejected from the nu- cleus What are the rows of the periodic table What are the columns of the periodic Who published the first periodic table, called? table called? and when did he do it? What is the first group on the periodic What is the second group on the What is the seventeenth group on the table, containing Li, Na, K, Rb, Cs, and periodic table, containing Be, Mg, Ca, periodic table, containing F, Cl, Br, I, Fr? Sr, Ba, and Ra? and At? Moving left to right across a period, What are the different blocks of the What are the six noble gases? does atomic radius usually decrease periodic table? or increase? What is the heaviest element to have How many elements does the periodic How many elements occur naturally? been observed in macroscopic table have? quantities? Metallic properties are related to lower What element is the most electronega- What is electronegativity? or higher values of ionization energy, tive? electronegativity and electron affinity? In 1994, what did the International What were the first discovered syn- What were the two original names of Union of Pure and Applied thetic elements , and when were they element 105, now known as dubnium? Chemistry (IUPAC) decide regarding first synthesized? element naming? Dmitri Mendeleev, in 1869 Groups Periods Halogens Alkaline earth metals Alkali metals The s-block, the d-block, the p-block, Helium, neon, argon, krypton, xenon, Decrease and the f-block and radon 114, though an additional four are Number 99, einsteinium 98 claimed to have been synthesized.
Recommended publications
  • New Conceptual Understanding of Lewis Acidity, Coordinate Covalent Bonding, and Catalysis Joshua A
    Duquesne University Duquesne Scholarship Collection Electronic Theses and Dissertations Summer 2009 New Conceptual Understanding of Lewis Acidity, Coordinate Covalent Bonding, and Catalysis Joshua A. Plumley Follow this and additional works at: https://dsc.duq.edu/etd Recommended Citation Plumley, J. (2009). New Conceptual Understanding of Lewis Acidity, Coordinate Covalent Bonding, and Catalysis (Doctoral dissertation, Duquesne University). Retrieved from https://dsc.duq.edu/etd/1052 This Immediate Access is brought to you for free and open access by Duquesne Scholarship Collection. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of Duquesne Scholarship Collection. For more information, please contact [email protected]. NEW CONCEPTUAL UNDERSTANDING OF LEWIS ACIDITY, COORDINATE COVALENT BONDING, AND CATALYSIS A Dissertation Submitted to the Bayer School of Natural and Environmental Sciences Duquesne University In partial fulfillment of the requirements for the degree of Doctor of Philosophy By Joshua A. Plumley August 2009 NEW CONCEPTUAL UNDERSTANDING OF LEWIS ACIDITY, COORDINATE COVALENT BONDING, AND CATALYSIS By Joshua A. Plumley Approved August 2009 __________________________________ __________________________________ Jeffrey D. Evanseck Ellen Gawalt Professor of Chemistry and Biochemistry Assistant Professor of Chemistry and Dissertation Director Biochemistry Committee Member Committee Member __________________________________ __________________________________ Douglas J. Fox
    [Show full text]
  • "The Atom and the Molecule " Di Gilbert N. Lewis Articolo Originale
    "The Atom and the Molecule " di Gilbert N. Lewis articolo originale Scritto da Roberto Poeti Domenica 20 Settembre 2009 22:43 - Ultimo aggiornamento Mercoledì 07 Ottobre 2009 20:40 The Atom and the Molecule by Gilbert N. Lewis Journal of the American Chemical Society Volume 38, 1916, pages 762-786 Received January 26, 1916 762 In a paper entitled "Valence and Tautomerism"1 I took occasion 1 This Journal, 35, 1448 (1913); see also the important article of Bray and Branch, Ibid, 35, 1440 (1913) 763 to point out the great importance of substituting for the conventional classification of chemical substances, as inorganic or organic, the more general classification which distinguishes between polar and nonpolar substances. The two classifications roughly coincide, since most inorganic substances are distinctly polar, while the majority of organic substances belong to the nonpolar class; thus potassium chloride represents the extreme polar type and methane the nonpolar. Nevertheless, there are many inorganic substances which, under ordinary circumstances, are predominantly nonpolar, and many organic substances which, at least in a certain part of the molecule, are strongly polar. This article was apparently unknown to Sir J.J. Thomson1 when he wrote, in 1914, an extremely interesting paper on the "Forces between Atoms and Chemical Affinity" in which he reached conclusions in striking accord with my own and discussed in considerable detail the theories of 1 / 21 "The Atom and the Molecule " di Gilbert N. Lewis articolo originale Scritto da Roberto Poeti Domenica 20 Settembre 2009 22:43 - Ultimo aggiornamento Mercoledì 07 Ottobre 2009 20:40 atomic and molecular structure which led him to those conclusions.
    [Show full text]
  • 1997) 150–163
    Eur. J. Phys. 18 (1997) 150–163. Printed in the UK PII: S0143-0807(97)80684-8 The chemists’ electron Theodore Arabatzis and Kostas Gavroglu Department of History and Philosophy of Science, University of Athens, Greece Received 6 January 1997, in final form 13 February 1997 Abstract. This paper narrates the way chemists have been Resum´ e.´ Dans cet article on narre comment l’electron´ avait using the electron to account for one of the most intriguing et´ e´ utilise´ par les chimistes, afin de rendre compte d’un problems, namely the bonding of two neutral atoms to form a probleme` intriguant, notamment celui de la liaison de deux molecule. The chemists’ attempts to account for the atomes neutres pour former une molecule.´ Les efforts des mechanism of the homopolar bond, first in the context of the chimistes de rendre compte du mecanisme´ de la liaison old quantum theory and after 1926 in the context of wave homopolaire, d’abord dans le contexte de la theorie´ quantique mechanics, brought the specter of reductionism to physics. ancienne, ensuite, apres´ 1926, dans le contexte de la We argue that the chemists’ successful appropriation of the mecanique´ ondulatoire, a fait entrer dans la Physique le electron strengthened, first, the autonomy of physical spectre du reductionnisme.´ Nous soutenons la these` que chemistry and, then, of quantum chemistry with respect to l’appropriation reussie´ de l’electron´ par les chimistes a physics. renforcee´ l’autonomie, par rapport a` la Physique, d’abord de la chimie physique et, ensuite, de la chimie quantique. 1. Introduction which was so appealing to the chemists, obliged the chemists to re-acquisition what they felt was theirs in The aim of Robert Millikan’s Faraday lecture before the first place.
    [Show full text]
  • The Atom's Ancestry
    1 The Atoms Ancestry What in the world is an atom? Or, more appropriately; what in the world is not an atom? Air, water, earth, people, robots—everything is made up of atoms. As early as 500 B.C. the Greeks speculated that matter can be split into smaller and smaller bite, but they expected a limit, beyond which it could not be further subdivided. Etymology of Atom We come to know from Aristotle that the founder of the atomic theory was Democritus and Leucippus. The word ‘atom’ is derived from atomos, ‘a’ = not and tomos = a cut; thereby meaning ‘indivisible’. The concept of atom that Western scientists accepted in broad outline from 1600s until 1900 originated with Greek philosophers in the 5th century. The atom was described as being hard; having a form, size, and weight and being in ceaseless motion. This speculation was replaced slowly by scientific theory supported by experiments and mathematical deductions. The Atomic Philosophy of Early Greeks Leucippus of Miletus is thought to have originated the atomic philosophy. His famous disciple, Democritus of Abdera, named the building blocks of matter. He believed that atoms were uniform, solid, hard, incompressible, and indestructible and keep moving in empty space in infinite numbers till stopped. Differences in atomic shape and size determined the various properties of matter. In Democritus’s philosophy, atoms existed not only for matter but also for such qualities as perception and the human soul. For example, sourness was supposed to be caused by needle-shaped atoms while the color white was believed to be composed of smooth- surfaced atoms.
    [Show full text]
  • Cubes, Eights, and Dots: a Student's Guide to the Octet Rule and Its
    DOCUMENT RESUME ED 247 134 SE 044 730" , AUTHOR Kooser,. Robert G.; Factor, Lance TITLE Cubes, Eights, and Dots: AStudent's Guide to the Octet Rule and Its History. SPONS AGENCY National Endowment for the Humanities(NFAH), Washington, D.C.; National ScienceFoundation, and Values in Science and Washington, DC. Ethics7 Technology Program. PUB DATE Jun 83 NOTE 25p. PUB TYPE Guides ClassrooMNUse Materials (For Learner). (051) EDRS PRICE MF01/PC01. Plus Postage. DESCRIPTORS *Chemical Bonding; *Chemistry; CollegeScience; Higher Education; High Schools;Science Education; *Science History; *Secondary SchoolScience IDENTIFIERS *Octet Rule ABSTRACT This exercise is designed to correctthe impression of many students thatscientific facts are unchanging. Every scientific fact has a history andits history shapes the formwhich the fact takes in a textbook.Thus, the history of the octetrule is traced to show that scientificknowledge is not a cast iron setof facts but rather a fluid bodyof information shaped bythe people who The exercise consists of areading and use it for specific purposes. answered by a set of discussionquestions.. The questions can be students or could form thebasis for a class discussionabout the issues raised. It is suggestedthat the exercise be used afterthe lesson on the octet rule andLewis dot structures. (JN) *********************************************************************** the best that can be made * * Reproductions supplied by EDRS are * * from the original document. *********************************************************************** CUBES,EIGHTS AND DOTS A Student's Guide to the OctetRule and its History U.S. DEPARTMENT OF EDUCATION NATIONAL INSTITUTE OF EDUCATION EDUCATIONAL RESOURCES INFORMATION CENTER (ERIC' This document has been reproducedas received horn the person or organization originating it Minor changes have been made to improve reproduetion quality.
    [Show full text]
  • Valence Bond Theory—Its Birth, Struggles with Molecular Orbital Theory, Its Present State and Future Prospects
    molecules Review Valence Bond Theory—Its Birth, Struggles with Molecular Orbital Theory, Its Present State and Future Prospects Sason Shaik 1,* , David Danovich 1 and Philippe C. Hiberty 2,* 1 Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel; [email protected] 2 CNRS, Institut de Chimie Physique UMR8000, Université Paris-Saclay, 91405 Orsay, France * Correspondence: [email protected] (S.S.); [email protected] (P.C.H.) Abstract: This essay describes the successive births of valence bond (VB) theory during 1916–1931. The alternative molecular orbital (MO) theory was born in the late 1920s. The presence of two seemingly different descriptions of molecules by the two theories led to struggles between the main proponents, Linus Pauling and Robert Mulliken, and their supporters. Until the 1950s, VB theory was dominant, and then it was eclipsed by MO theory. The struggles will be discussed, as well as the new dawn of VB theory, and its future. Keywords: valence bond; molecular orbital; Lewis; electron-pair bonds; Pauling; Mulliken; Hund; Hückel 1. Introduction Citation: Shaik, S.; Danovich, D.; This essay tells briefly a story of the emerging two major quantum mechanical theories, Hiberty, P.C. Valence Bond valence bond (VB) theory and molecular orbital (MO) theory, which look as two different Theory—Its Birth, Struggles with descriptions of the same reality, but are actually not. We discuss the struggles between Molecular Orbital Theory, Its Present the two main groups of followers of Pauling and Mulliken, and the ups and downs in the State and Future Prospects. Molecules popularity of the two methods among chemists, and then the fall of VB theory only to be 2021, 26, 1624.
    [Show full text]
  • The Many Faces of the Bohr Atom
    1 The many faces of the Bohr atom Helge Kragh The atomic model that Bohr proposed in 1913 constituted a break with all earlier conceptions of the atom. Keeping to the theory’s basic postulates – the stationary states and the frequency condition – he conceived the model as preliminary and immediately began developing and modifying it. Strictly speaking there was no single Bohr atom but rather a series of different models sharing some common features. In this paper I start with calling attention to some less well known aspects of Bohr’s early model of one-electron atoms the significance of which only became recognized after his death in 1962. I then briefly sketch how he abandoned the ring model for many-electron atoms about 1920 and subsequently went on developing the ambitious orbital model that he thought would unravel the secrets of the periodic system. Bohr’s model of 1921-1922 marked the culmination of the orbital atom within the old quantum theory, but it would soon be replaced by a symbolic and non- visualizable view of atomic structure leading to the atom of quantum mechanics. 1. Rydberg atoms and isotope effect Among the unusual features of the atom that Bohr presented in the first part of his trilogy of 1913 was that the hydrogen atom, and other atoms as well, did not have a fixed size. For the radius of a one-electron atom with nuclear charge Ze he derived the expression where = 1, 2, 3,… and the other symbols have their usual meanings. For a hydrogen atom (Z = 1) in its ground state = 1 he found the value a1 = 0.55 × 10-8 cm as compared to the modern value 0.53 × 10-8 cm.
    [Show full text]
  • Chemistry 1B Fall 2012 Lecture 9
    Chemistry 1B Fall 2012 Lecture 9 bonding in molecules • Chapter 13 (pp 593-612)– Overview of bonding and Chemistry 1B ionic bonding (lect 9) • Chapter 13 (pp 612-650)- “Classical” picture of Fall 2012 bonding and molecular geometry (lect 10-12) Lecture 9 • Chapter 19 (pp 933-937;- Bonding in transition metal 946-948; complexes (lect 13-14) (chapter 13; pp 593-612) 958-966) [596-614]7th • Chapter 14- Quantum mechanical description of bonding 2 3 types of bonding general properties of the 3-types of bonding (Silberberg fig.9.2) • Ionic • Covalent • Metallic 4 5 general properties of the 3-types of bonding (Silberberg fig.9.2) hello Lewis electron-dot diagrams 6 7 1 Chemistry 1B Fall 2012 Lecture 9 G. N. Lewis- UC Berkeley G.N. Lewis 1916 The Atom and the Molecule by Gilbert N. Lewis Journal of the American Chemical Society Volume 38, 1916, pages 762-786 Received January 26, 1916 8 9 G.N. Lewis 1916 G.N. Lewis 1916 The Cubical Atom. The Cubical Atom. A number of years ago, to account for the striking fact which has become known as Abegg's law of valence and countervalence, and according to which the total difference between the maximum negative and positive …….. valences or polar numbers of an element is frequently eight and is in no case more than eight, I designed what may be called the theory of the cubical atom. This theory, while it has become familiar to a number of my The pictures of atomic structure which are reproduced colleagues, has never been published, partly because it was in many in Fig.
    [Show full text]
  • Pauli Exclusion Principle - Wikipedia, the Free Encyclopedia 5/24/10 10:48 AM
    Pauli exclusion principle - Wikipedia, the free encyclopedia 5/24/10 10:48 AM Pauli exclusion principle From Wikipedia, the free encyclopedia The Pauli exclusion principle is a quantum Quantum mechanics mechanical principle formulated by the Austrian physicist Wolfgang Pauli in 1925. In its simplest form for electrons in a single atom, it states that no Uncertainty principle two electrons can have the same four quantum Introduction · Mathematical formulation numbers, that is, if n, l, and ml are the same, ms must be different such that the electrons have Background opposite spins. More generally, no two identical Classical mechanics fermions (particles with half-integer spin) may Old quantum theory occupy the same quantum state simultaneously. A Interference · Bra-ket notation more rigorous statement of this principle is that, for Hamiltonian two identical fermions, the total wave function is anti-symmetric. Fundamental concepts Quantum state · Wave function In contrast, integer spin particles, bosons are not Superposition · Entanglement subject to the Pauli exclusion principle. For bosons Measurement · Uncertainty any number of identical particles can occupy the Exclusion · Duality same quantum state, this is seen in for instance Decoherence · Ehrenfest theorem · lasers and Bose-Einstein condensation. Tunnelling Experiments Contents Double-slit experiment Davisson–Germer experiment 1 Overview Stern–Gerlach experiment 2 History Bell's inequality experiment 3 Connection to quantum state symmetry Popper's experiment 3.1 The Pauli principle
    [Show full text]
  • A View of Covalent and Ionic Bonding from Maximum Probability Domains M
    A view of covalent and ionic bonding from Maximum Probability Domains M. Menéndez, A. Martín Pendás, Benoît Braïda, A. Savin To cite this version: M. Menéndez, A. Martín Pendás, Benoît Braïda, A. Savin. A view of covalent and ionic bonding from Maximum Probability Domains. Computational and Theoretical Chemistry, Elsevier, 2015, 1053, pp.142-149. 10.1016/j.comptc.2014.10.004. hal-01627697 HAL Id: hal-01627697 https://hal.archives-ouvertes.fr/hal-01627697 Submitted on 21 Nov 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. A view of covalent and ionic bonding from Maximum Probability Domains a,b a b,c, b,c M. Menéndez , A. Martín Pendás , B. Braïda ⇑, A. Savin a Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, 33006 Oviedo, Spain b Sorbonne Universités, UPMC Univ. Paris 06, UMR 7616, LCT, F-75005 Paris, France c CNRS, UMR 7616, LCT, F-75005 Paris, France abstract Connecting the accurate Quantum Mechanics to the chemical view is the first of foremost purposes of interpretative methods in general, and topological analysis in particular. In this field of methods, the Maximum Probability Domains (MPD) analysis, is conceptually appealing but has not been extensively applied yet.
    [Show full text]
  • Time-Dependent Electron Localisation Function: a Tool to Visualise and Analyse Ultrafast Processes
    Time-dependent electron localisation function: A tool to visualise and analyse ultrafast processes Alberto Castro,1 Tobias Burnus,2 M. A. L. Marques,3 and E. K. U. Gross4 1Institut f¨ur Theoretische Physik, Fachbereich Physik der Freie Universit¨at Berlin, Arnimallee 14, D-14195 Berlin (Germany) 2Physikalisches Institut, Universit¨at zu K¨oln, Z¨ulpicher Str. 77, D-50937 K¨oln (Germany) 3Departamento de F´ısica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal) 4Institut f¨ur Theoretische Physik, Fachbereich Physik der Freie Universit¨at Berlin, Arnimallee 14, 14195 Berlin (Germany) The time-dependent electron localisation function (TDELF) is a generalisation of the electron localisation function (ELF) proposed by A. D. Becke and K. E. Edge- combe [J. Chem. Phys. 92, 5397 (1990)], which allows for time-resolved observation of the formation, the modulation, and the breaking of chemical bonds, and can thus provide a visual understanding of complex reactions involving the dynamics of ex- cited states. We discuss the rationale behind the definition of the ELF, and sketch the general derivation that permits its use for the analysis of time-dependent processes. We present some examples: First, ground-state results showing the characteristic topology of the ELF for various prototypical chemical cases. Secondly, the time- dependent ELF of a few processes is monitored, which demonstrates how it permits to enhance our visual intuition of the electronic behaviour during fast phenomena: the chemical reaction leading to the formation of the water molecule following the collision of a proton and a hydroxide ion, the capture of a proton by the lone pair of the electron rich, smallest imine or unprotonated Schiff base (formaldimine), and the bond breaking of the ethyne triple bond due to the interaction with a strong and ultrashort laser pulse.
    [Show full text]
  • Presentation of Origin of the Covalent Bond in Turkish General Chemistry Textbooks: a History and Philosophy of Science Perspective
    emergent topics on chemistry education Educ. quím., publicado en línea el 13 de abril de 2012 [nature of chemistry: history and philosophy © Universidad Nacional Autónoma de México, ISSNE 1870-8404 of chemistry] Presentation of Origin of the Covalent Bond in Turkish General Chemistry Textbooks: A History and Philosophy of Science Perspective Bayram Coştu1 and Mansoor Niaz2 ABSTRACT The main objectives of this study are 1) to develop a perspective based on history and philosophy of science (HPS) considerations in order to understand the postulation of the covalent (shared pair) bond by Lewis; 2) to formulate criteria based on the HPS perspective that could be useful in the evaluation of general chemistry textbooks; and 3) to evaluate 27 general chemistry textbooks (published in Turkey) utilizing the criteria based on the HPS perspective. Results obtained showed that most of the general chemistry textbooks did not present the origin of the covalent bond based on a HPS perspective. Also, the textbooks mostly follow an inductivist interpretation of the origin of the covalent bond. It is plausible to suggest that textbook presentations based on a HPS perspective can perhaps facilitate students’ interest in the subject and hence lead to sound conceptual understanding. KEYWORDS: historical reconstruction, covalent bond, Turkish and U.S.A. general chemistry textbooks Resumen (Presentación del origen del enlace cova- charged electrons. Formation of the ionic bond leads to the lente en los libros de texto turcos de Química Gene- lowering of energy because of electrostatic attraction between ral: Una perspectiva de la historia y filosofía de la ions of opposite charge.
    [Show full text]