An Introduction to Chemistry An Introduction to Chemistry By Peter B. Moore An Introduction to Chemistry By Peter B. Moore This book first published 2020 Cambridge Scholars Publishing Lady Stephenson Library, Newcastle upon Tyne, NE6 2PA, UK British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Copyright © 2020 by Peter B. Moore All rights for this book reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the copyright owner. ISBN (10): 1-5275-4551-2 ISBN (13): 978-1-5275-4551-9 TABLE OF CONTENTS Preface ....................................................................................................... xii Notes for the Reader ................................................................................. xiv Acknowledgements .................................................................................. xvi Part I: Matter Chapter One ................................................................................................. 2 Origins: From Boyle to Lavoisier What is Chemistry? ................................................................................ 2 Humans have been doing chemistry forever .......................................... 3 What is an element? ............................................................................... 5 The mysteries of fire and air resolved .................................................. 11 Chapter Two .............................................................................................. 18 The Return of the Atom John Dalton’s atom .............................................................................. 18 Atomic weights and molecular formulas ............................................. 22 The struggle to obtain reliable atomic weights .................................... 27 Electricity ............................................................................................. 33 Avogadro embraced, reliable atomic weights at last............................ 35 Chapter Three ............................................................................................ 38 The Periodic Table The invention of the periodic table ...................................................... 38 The periodic table completed ............................................................... 43 The periodic table today ...................................................................... 46 Chapter Four .............................................................................................. 48 On the Structure of Atoms Ions and electrons ................................................................................ 48 The nucleus discovered ........................................................................ 55 Why aren’t atomic weight perfect integers? ........................................ 60 vi Table of Contents Chapter Five .............................................................................................. 65 Electrons and Atoms The planetary atom .............................................................................. 65 Lewis and the covalent bond ............................................................... 67 Extending the Lewis formalism ........................................................... 77 Some final comments .......................................................................... 81 Chapter Six ................................................................................................ 83 The Quantum Plank and Bohr .................................................................................... 83 De Broglie ............................................................................................ 89 The wave equation ............................................................................... 92 Big atoms and the Pauli principle ........................................................ 97 Chapter Seven .......................................................................................... 105 The Periodic Table Revisited On the form of the table ..................................................................... 105 Ionization energies ............................................................................. 109 Electron affinity ................................................................................. 113 Electronegativity ................................................................................ 115 Chapter Eight ........................................................................................... 118 Molecular Quantum Mechanics Quantum mechanics explains the covalent bond ............................... 118 Diatomic molecules ........................................................................... 120 Molecular orbitals .............................................................................. 122 Valence bond theory and hybrid atomic orbitals ............................... 129 Multi-atom molecular orbitals ........................................................... 133 Chapter Nine ............................................................................................ 140 Molecular Geometry and Coordination Complexes Steric numbers ................................................................................... 140 Isomers............................................................................................... 143 Coordination complexes .................................................................... 147 Valence bond theory and coordination complexes ............................ 152 Crystal field theory ............................................................................ 155 Ligand field theory ............................................................................ 157 An Introduction to Chemistry vii Chapter Ten ............................................................................................. 165 Liquids and Solids Phases ................................................................................................ 165 On the sizes of atoms and molecules ................................................. 166 The dispersion force .......................................................................... 168 Ionic solids ......................................................................................... 170 Polar solids ........................................................................................ 172 Hydrogen bonds ................................................................................. 172 Covalent solids................................................................................... 174 Hybrid solids ...................................................................................... 176 Metals ................................................................................................ 179 Liquids and glasses ............................................................................ 183 Part II: Energy Chapter Eleven ........................................................................................ 190 Heat, Temperature, and Gases Thermodynamics and steam engines ................................................. 190 The difference between heat and temperature ................................... 195 Caloric overthrown ............................................................................ 201 The kinetic theory of gases ................................................................ 203 Chapter Twelve ....................................................................................... 208 The First Law of Thermodynamics The first law at last ............................................................................ 208 Chemical calorimetry ......................................................................... 212 Heat capacities ................................................................................... 215 Hess’s law .......................................................................................... 217 Chapter Thirteen ...................................................................................... 224 The Second Law of Thermodynamics Water wheels and steam engines ....................................................... 224 Carnot ................................................................................................ 225 The second law at last ........................................................................ 229 Entropy .............................................................................................. 232 The molecular meaning of entropy .................................................... 234 Reaction entropies and the third law .................................................. 240 viii Table of Contents Chapter Fourteen ..................................................................................... 246 Free Energies Gibbs and Helmholtz free energies .................................................... 246 Free energies and equilibrium constants ............................................ 250 Thermodynamic cycles and temperature changes .............................. 255 Solutions 101 ..................................................................................... 257 Equilibrium constants in solution ...................................................... 261 Non-ideal