Molecular Structure Introduction
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Unit 3 Notes: Periodic Table Notes John Newlands Proposed an Organization System Based on Increasing Atomic Mass in 1864
Unit 3 Notes: Periodic Table Notes John Newlands proposed an organization system based on increasing atomic mass in 1864. He noticed that both the chemical and physical properties repeated every 8 elements and called this the ____Law of Octaves ___________. In 1869 both Lothar Meyer and Dmitri Mendeleev showed a connection between atomic mass and an element’s properties. Mendeleev published first, and is given credit for this. He also noticed a periodic pattern when elements were ordered by increasing ___Atomic Mass _______________________________. By arranging elements in order of increasing atomic mass into columns, Mendeleev created the first Periodic Table. This table also predicted the existence and properties of undiscovered elements. After many new elements were discovered, it appeared that a number of elements were out of order based on their _____Properties_________. In 1913 Henry Mosley discovered that each element contains a unique number of ___Protons________________. By rearranging the elements based on _________Atomic Number___, the problems with the Periodic Table were corrected. This new arrangement creates a periodic repetition of both physical and chemical properties known as the ____Periodic Law___. Periods are the ____Rows_____ Groups/Families are the Columns Valence electrons across a period are There are equal numbers of valence in the same energy level electrons in a group. 1 When elements are arranged in order of increasing _Atomic Number_, there is a periodic repetition of their physical and chemical -
Structure and Bonding Electron Configurations in the Periodic Table
Structure and Bonding The study of organic chemistry must at some point extend to the molecular level, for the physical and chemical properties of a substance are ultimately explained in terms of the structure and bonding of molecules. This module introduces some basic facts and principles that are needed for a discussion of organic molecules. Electronic Configurations Electron Configurations in the Periodic Table 1A 2A 3A 4A 5A 6A 7A 8A 1 2 H He 1 2 1s 1s 3 4 5 6 7 8 9 10 Li Be B C N O F Ne 2 2 2 2 2 2 2 2 1s 1s 1s 1s 1s 1s 1s 1s 2s1 2s2 2s22p1 2s22p2 2s22p3 2s22p4 2s22p5 2s22p6 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar [Ne] [Ne] [Ne] [Ne] [Ne] [Ne] [Ne] [Ne] 3s1 3s2 3s23p1 3s23p2 3s23p3 3s23p4 3s23p5 3s23p6 Four elements, hydrogen, carbon, oxygen and nitrogen, are the major components of most organic compounds. Consequently, our understanding of organic chemistry must have, as a foundation, an appreciation of the electronic structure and properties of these elements. The truncated periodic table shown above provides the orbital electronic structure for the first eighteen elements (hydrogen through argon). According to the Aufbau principle, the electrons of an atom occupy quantum levels or orbitals starting from the lowest energy level, and proceeding to the highest, with each orbital holding a maximum of two paired electrons (opposite spins). Electron shell #1 has the lowest energy and its s-orbital is the first to be filled. -
VSEPR Theory
VSEPR Theory The valence-shell electron-pair repulsion (VSEPR) model is often used in chemistry to predict the three dimensional arrangement, or the geometry, of molecules. This model predicts the shape of a molecule by taking into account the repulsion between electron pairs. This handout will discuss how to use the VSEPR model to predict electron and molecular geometry. Here are some definitions for terms that will be used throughout this handout: Electron Domain – The region in which electrons are most likely to be found (bonding and nonbonding). A lone pair, single, double, or triple bond represents one region of an electron domain. H2O has four domains: 2 single bonds and 2 nonbonding lone pairs. Electron Domain may also be referred to as the steric number. Nonbonding Pairs Bonding Pairs Electron domain geometry - The arrangement of electron domains surrounding the central atom of a molecule or ion. Molecular geometry - The arrangement of the atoms in a molecule (The nonbonding domains are not included in the description). Bond angles (BA) - The angle between two adjacent bonds in the same atom. The bond angles are affected by all electron domains, but they only describe the angle between bonding electrons. Lewis structure - A 2-dimensional drawing that shows the bonding of a molecule’s atoms as well as lone pairs of electrons that may exist in the molecule. Provided by VSEPR Theory The Academic Center for Excellence 1 April 2019 Octet Rule – Atoms will gain, lose, or share electrons to have a full outer shell consisting of 8 electrons. When drawing Lewis structures or molecules, each atom should have an octet. -
Chemistry Third Marking Period Review Sheet Spring, Mr
Chemistry Third Marking Period Review Sheet Spring, Mr. Wicks Chapters 7-8: Ionic and Covalent Bonding • I can explain the difference between core electrons and valence electrons. • I can write Lewis dot symbols for atoms of particular elements and show the gain or loss of electrons to form ionic compounds. • I can compare and contrast ionic and molecular compounds. See Table 1. • I can describe ionic and covalent bonding and explain the differences between them. • I can compare and contrast the properties of ionic and molecular compounds. • I can predict trends in bond length when comparing carbon-carbon single, double, and triple bonds. Table 1: Comparing Ionic and Molecular Compounds Ionic Compounds Molecular Compounds Bonding Type: Ionic Bonding Covalent Bonding In this type of bonding, electrons are _____: Transferred Shared Type(s) of Elements Involved: Metal + Nonmetal Elements Nonmetal Elements Comparison of Larger Smaller electronegativity differences: Comparison of Properties: a. Melting and boiling points: a. Higher a. Lower b. Hardness: b. Harder b. Softer c. Conduction of electricity: c. When molten or dissolved in c. Molecular compounds do water, ionic compounds tend to not conduct electricity. conduct electricity. • I can apply trends for electronegativity in the periodic table to solve homework problems. • I can use electronegativity differences to classify bonds as nonpolar covalent, polar covalent, and ionic. See Table 2. Table 2: Classifying Bonds Using Electronegativity Differences Electronegativity Difference Bond Type 0 - 0.2 Nonpolar covalent bond 0.3 - 1.9 Polar covalent bond ≥ 2.0 Ionic bond Chemistry Third Marking Period Review Sheet, Page 2 • I can apply the octet rule to write Lewis structures for molecular compounds and polyatomic ions. -
Computational Studies of Three Chemical Systems
Computational Studies of Three Chemical Systems _______________________________________ A Dissertation Presented to The Faculty of the Graduate School University of Missouri-Columbia _______________________________________________________ In Partial Fulfillment Of the Requirements for the Degree Doctor of Philosophy _____________________________________________________ by Haunani Thomas Prof. Carol A. Deakyne, Dissertation Supervisor December 2011 The undersigned, appointed by the dean of the Graduate School, have examined the dissertation entitled COMPUTATIONAL STUDIES OF THREE CHEMICAL SYSTEMS Presented by Haunani Thomas, a candidate for the degree of doctor of philosophy of Chemistry, and hereby certify that, in their opinion, it is worthy of acceptance. Professor Carol Deakyne (Chair) Professor John Adams (Member) Professor Michael Greenlief (Member) Professor Giovanni Vignale (Outside Member) ACKNOWLEDGEMENTS I am forever indebted to my dissertation supervisor, Professor Carol Deakyne, for her guidance and support. She has been an excellent and patient mentor through the graduate school process, always mindful of the practical necessities of my progress, introducing me to the field of Chemistry, and allowing me to advance professionally through attendance and presentations at ACS meetings. I am fully aware that, in this respect, not all graduate students are as fortunate as I have been. I am also grateful to Professor John Adams for all his support and teaching throughout my graduate career. I am appreciative of my entire committee, Professor Deakyne, Professor Adams, Professor Michael Greenlief, and Professor Giovanni Vignale, for their sound advice, patience, and flexibility. I would also like to thank my experimental collaborators and their groups, Professor Joel Liebman of the University of Maryland, Baltimore County, Professor Michael Van Stip Donk of Wichita State University, and Professor Jerry Atwood of the University of Missouri – Columbia. -
8.3 Bonding Theories >
8.3 Bonding Theories > Chapter 8 Covalent Bonding 8.1 Molecular Compounds 8.2 The Nature of Covalent Bonding 8.3 Bonding Theories 8.4 Polar Bonds and Molecules 1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 8.3 Bonding Theories > Molecular Orbitals Molecular Orbitals How are atomic and molecular orbitals related? 2 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 8.3 Bonding Theories > Molecular Orbitals • The model you have been using for covalent bonding assumes the orbitals are those of the individual atoms. • There is a quantum mechanical model of bonding, however, that describes the electrons in molecules using orbitals that exist only for groupings of atoms. 3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 8.3 Bonding Theories > Molecular Orbitals • When two atoms combine, this model assumes that their atomic orbitals overlap to produce molecular orbitals, or orbitals that apply to the entire molecule. 4 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 8.3 Bonding Theories > Molecular Orbitals Just as an atomic orbital belongs to a particular atom, a molecular orbital belongs to a molecule as a whole. • A molecular orbital that can be occupied by two electrons of a covalent bond is called a bonding orbital. 5 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 8.3 Bonding Theories > Molecular Orbitals Sigma Bonds When two atomic orbitals combine to form a molecular orbital that is symmetrical around the axis connecting two atomic nuclei, a sigma bond is formed. • Its symbol is the Greek letter sigma (σ). -
Chemical Bonding & Chemical Structure
Chemistry 201 – 2009 Chapter 1, Page 1 Chapter 1 – Chemical Bonding & Chemical Structure ings from inside your textbook because I normally ex- Getting Started pect you to read the entire chapter. 4. Finally, there will often be a Supplement that con- If you’ve downloaded this guide, it means you’re getting tains comments on material that I have found espe- serious about studying. So do you already have an idea cially tricky. Material that I expect you to memorize about how you’re going to study? will also be placed here. Maybe you thought you would read all of chapter 1 and then try the homework? That sounds good. Or maybe you Checklist thought you’d read a little bit, then do some problems from the book, and just keep switching back and forth? That When you have finished studying Chapter 1, you should be sounds really good. Or … maybe you thought you would able to:1 go through the chapter and make a list of all of the impor- tant technical terms in bold? That might be good too. 1. State the number of valence electrons on the following atoms: H, Li, Na, K, Mg, B, Al, C, Si, N, P, O, S, F, So what point am I trying to make here? Simply this – you Cl, Br, I should do whatever you think will work. Try something. Do something. Anything you do will help. 2. Draw and interpret Lewis structures Are some things better to do than others? Of course! But a. Use bond lengths to predict bond orders, and vice figuring out which study methods work well and which versa ones don’t will take time. -
A New Way for Probing Bond Strength J
A New Way for Probing Bond Strength J. Klein, H. Khartabil, J.C. Boisson, J. Contreras-Garcia, Jean-Philip Piquemal, E. Henon To cite this version: J. Klein, H. Khartabil, J.C. Boisson, J. Contreras-Garcia, Jean-Philip Piquemal, et al.. A New Way for Probing Bond Strength. Journal of Physical Chemistry A, American Chemical Society, 2020, 124 (9), pp.1850-1860. 10.1021/acs.jpca.9b09845. hal-02377737 HAL Id: hal-02377737 https://hal.archives-ouvertes.fr/hal-02377737 Submitted on 27 Mar 2021 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 New Way for Probing Bond Strength Johanna Klein,y Hassan Khartabil,y Jean-Charles Boisson,z Julia Contreras-Garc´ıa,{ Jean-Philip Piquemal,{ and Eric H´enon∗,y yInstitut de Chimie Mol´eculaire de Reims UMR CNRS 7312, Universit´ede Reims Champagne-Ardenne, Moulin de la Housse 51687 Reims Cedex 02 BP39 (France) zCReSTIC EA 3804, Universit´ede Reims Champagne-Ardenne, Moulin de la Housse 51687 Reims Cedex 02 BP39 (France) {Sorbonne Universit´es,UPMC, Laboratoire de Chimie Th´eoriqueand UMR CNRS 7616, 4 Pl Jussieu, 75252 Paris Cedex 05(France) E-mail: [email protected] Phone: +33(3)26918497 1 Abstract The covalent chemical bond is intimately linked to electron sharing between atoms. -
Searching Coordination Compounds
CAS ONLINEB Available on STN Internationalm The Scientific & Technical Information Network SEARCHING COORDINATION COMPOUNDS December 1986 Chemical Abstracts Service A Division of the American Chemical Society 2540 Olentangy River Road P.O. Box 3012 Columbus, OH 43210 Copyright O 1986 American Chemical Society Quoting or copying of material from this publication for educational purposes is encouraged. providing acknowledgment is made of the source of such material. SEARCHING COORDINATION COMPOUNDS prepared by Adrienne W. Kozlowski Professor of Chemistry Central Connecticut State University while on sabbatical leave as a Visiting Educator, Chemical Abstracts Service Table of Contents Topic PKEFACE ............................s.~........................ 1 CHAPTER 1: INTRODUCTION TO SEARCHING IN CAS ONLINE ............... 1 What is Substructure Searching? ............................... 1 The Basic Commands .............................................. 2 CHAPTEK 2: INTKOOUCTION TO COORDINATION COPPOUNDS ................ 5 Definitions and Terminology ..................................... 5 Ligand Characteristics.......................................... 6 Metal Characteristics .................................... ... 8 CHAPTEK 3: STKUCTUKING AND REGISTKATION POLICIES FOR COORDINATION COMPOUNDS .............................................11 Policies for Structuring Coordination Compounds ................. Ligands .................................................... Ligand Structures........................................... Metal-Ligand -
Periodic Trends Lab CHM120 1The Periodic Table Is One of the Useful
Periodic Trends Lab CHM120 1The Periodic Table is one of the useful tools in chemistry. The table was developed around 1869 by Dimitri Mendeleev in Russia and Lothar Meyer in Germany. Both used the chemical and physical properties of the elements and their tables were very similar. In vertical groups of elements known as families we find elements that have the same number of valence electrons such as the Alkali Metals, the Alkaline Earth Metals, the Noble Gases, and the Halogens. 2Metals conduct electricity extremely well. Many solids, however, conduct electricity somewhat, but nowhere near as well as metals, which is why such materials are called semiconductors. Two examples of semiconductors are silicon and germanium, which lie immediately below carbon in the periodic table. Like carbon, each of these elements has four valence electrons, just the right number to satisfy the octet rule by forming single covalent bonds with four neighbors. Hence, silicon and germanium, as well as the gray form of tin, crystallize with the same infinite network of covalent bonds as diamond. 3The band gap is an intrinsic property of all solids. The following image should serve as good springboard into the discussion of band gaps. This is an atomic view of the bonding inside a solid (in this image, a metal). As we can see, each of the atoms has its own given number of energy levels, or the rings around the nuclei of each of the atoms. These energy levels are positions that electrons can occupy in an atom. In any solid, there are a vast number of atoms, and hence, a vast number of energy levels. -
Electron Configurations, Orbital Notation and Quantum Numbers
5 Electron Configurations, Orbital Notation and Quantum Numbers Electron Configurations, Orbital Notation and Quantum Numbers Understanding Electron Arrangement and Oxidation States Chemical properties depend on the number and arrangement of electrons in an atom. Usually, only the valence or outermost electrons are involved in chemical reactions. The electron cloud is compartmentalized. We model this compartmentalization through the use of electron configurations and orbital notations. The compartmentalization is as follows, energy levels have sublevels which have orbitals within them. We can use an apartment building as an analogy. The atom is the building, the floors of the apartment building are the energy levels, the apartments on a given floor are the orbitals and electrons reside inside the orbitals. There are two governing rules to consider when assigning electron configurations and orbital notations. Along with these rules, you must remember electrons are lazy and they hate each other, they will fill the lowest energy states first AND electrons repel each other since like charges repel. Rule 1: The Pauli Exclusion Principle In 1925, Wolfgang Pauli stated: No two electrons in an atom can have the same set of four quantum numbers. This means no atomic orbital can contain more than TWO electrons and the electrons must be of opposite spin if they are to form a pair within an orbital. Rule 2: Hunds Rule The most stable arrangement of electrons is one with the maximum number of unpaired electrons. It minimizes electron-electron repulsions and stabilizes the atom. Here is an analogy. In large families with several children, it is a luxury for each child to have their own room. -
Atomic Structure and Bonding
IM2665 Chemistry of Nanomaterials Atomic Structure and Bonding Assoc. Prof. Muhammet Toprak Division of Functional Materials KTH Royal Institute of Technology Background • Electromagnetic waves • Materials wave motion, • Quantified energy and – Louis de Broglie (1892-1987) photons • Uncertainity principle – Max Planck (1858-1947) – Werner Heisenberg (1901-1976) – Albert Einstein (1879-1955) • Schrödinger equation • Bohr’s atom model – Erwin Schrödinger (1887-1961) – Niels Bohr (1885-1962) IM2657 Nanostr. Mater. & Self Assembly 2 Electromagnetic Spectrum Visible light is only a small part of the Electromagnetic Spectrum IM2657 Nanostr. Mater. & Self Assembly 3 Electromagnetic Waves • Wavemotion is defined by • Calculations – ν = Frequency ( Hz) – c = ν × λ – λ = wavelength (m) – c = 3,00 × 108 m/s (speed of light) IM2657 Nanostr. Mater. & Self Assembly 4 Quantified Energy and Photons • E = h × ν; where h = 6,63 × 10-34 J s (Planck’s constant) • Photoelectric Effect (1905) IM2657 Nanostr. Mater. & Self Assembly 5 Thomson´s Pudding Model For a helium atom, the model proposes a large spherical cloud with two units of positive charge. Th e two electrons lie on a line through the center of the cloud. The loss of one electron produces the He+1 ion, with the remaining electron at the center of the cloud. The loss of a second electron prod uces He+2 , in which there is just a cloud of positive charge. IM2657 Nanostr. Mater. & Self Assembly 6 Rutherford’s Experiment The notion that atoms consist of very small nuclei containing protons and neutrons surrounded by a much larger cloud of electrons was IM2657 Nanostr. Mater. & Self Assembly 7 developed from an α particle scattering experiment.