The Britannica Guide to the Atom (Physics Explained)

Common to all matter and its smallest and most fundamental unit, the atom determines the properties of a substance and how it responds to other materials and stimuli. Dividing the atom further reveals several smaller particles whose activity forms the heart of nuclear physics. Readers will discover the structure of the atom as well as the ways in which its electrons, protons, and neutrons facilitate both radioactivity and nuclear reactions, both of which have been crucial to technological advancements since the 20th century. TITLE......Page 4 COPYRIGHT......Page 5 CONTENTS......Page 6 INTRODUCTION......Page 13 WHAT IS AN ATOM?......Page 22 THE ATOMIC PHILOSOPHY OF THE EARLY GREEKS......Page 23 THE EMERGENCE OF EXPERIMENTAL SCIENCE......Page 25 EXPERIMENTAL FOUNDATION OF ATOMIC CHEMISTRY......Page 27 ATOMIC WEIGHTS AND THE PERIODIC TABLE......Page 31 KINETIC THEORY OF GASES......Page 33 SIZE OF ATOMS......Page 36 ELECTRIC PROPERTIES OF ATOMS......Page 38 LIGHT AND SPECTRAL LINES......Page 39 DISCOVERY OF ELECTRONS......Page 42 MILLIKAN OIL-DROP EXPERIMENT......Page 44 IDENTIFICATION OF POSITIVE IONS......Page 46 DISCOVERY OF RADIOACTIVITY......Page 47 MODELS OF ATOMIC STRUCTURE......Page 50 RUTHERFORD’S NUCLEAR MODEL......Page 51 MOSELEY’S X-RAY STUDIES......Page 54 BOHR’S SHELL MODEL......Page 55 THE LAWS OF QUANTUM MECHANICS......Page 62 SCHRÖDINGER’S WAVE EQUATION......Page 64 ANTIPARTICLES AND THE ELECTRON’S SPIN......Page 66 STRUCTURE OF THE NUCLEUS......Page 67 QUANTUM FIELD THEORY AND THE STANDARD MODEL......Page 69 CHAPTER 2 THE ATOM: COMPONENTS AND PROPERTIES......Page 72 ATOMIC MASS AND ISOTOPES......Page 73 CHARGE, MASS, AND SPIN......Page 74 ORBITS AND ENERGY LEVELS......Page 76 ELECTRON SHELLS......Page 78 ATOMIC BONDS......Page 80 CONDUCTORS AND INSULATORS......Page 84 MAGNETIC PROPERTIES......Page 85 THE NUCLEUS......Page 86 NUCLEAR SHELL MODEL......Page 87 RADIOACTIVE DECAY......Page 89 NUCLEAR ENERGY......Page 91 CHAPTER 3 ISOTOPES......Page 93 THE DISCOVERY OF ISOTOPES......Page 94 NUCLEAR STABILITY......Page 97 RADIOACTIVE ISOTOPES......Page 100 ELEMENTAL AND ISOTOPIC ABUNDANCES......Page 101 VARIATIONS IN ISOTOPIC ABUNDANCES......Page 105 MASS FRACTIONATION......Page 106 PHYSICAL PROPERTIES ASSOCIATED WITH ISOTOPES......Page 108 EFFECT OF ISOTOPES ON ATOMIC AND MOLECULAR SPECTRA......Page 110 MOLECULAR VIBRATIONS......Page 112 IMPORTANCE IN THE STUDY OF POLYATOMIC MOLECULES......Page 113 CHEMICAL EFFECTS OF ISOTOPIC SUBSTITUTION......Page 114 EFFECT OF ISOTOPIC SUBSTITUTION ON REACTION RATES......Page 116 MASS SPECTROMETRY......Page 118 DISTILLATION......Page 119 GASEOUS DIFFUSION......Page 120 GAS CENTRIFUGATION......Page 121 PHOTOCHEMICAL ENRICHMENT METHODS......Page 122 THE NATURE OF RADIOACTIVE EMISSIONS......Page 124 ALPHA DECAY......Page 125 BETA-MINUS DECAY......Page 126 ISOMERIC TRANSITIONS......Page 127 ELECTRON CAPTURE......Page 128 SPONTANEOUS FISSION......Page 130 SPECIAL BETA-DECAY PROCESSES......Page 131 HEAVY-ION RADIOACTIVITY......Page 132 OCCURRENCE OF RADIOACTIVITY......Page 133 ENERGY RELEASE IN RADIOACTIVE TRANSITIONS......Page 136 CALCULATION AND MEASUREMENT OF ENERGY......Page 137 ABSOLUTE NUCLEAR BINDING ENERGY......Page 140 THE LIQUID-DROP MODEL......Page 141 THE SHELL MODEL......Page 143 THE COLLECTIVE MODEL......Page 145 RATES OF RADIOACTIVE TRANSITIONS......Page 146 EXPONENTIAL-DECAY LAW......Page 147 MEASUREMENT OF HALF-LIFE......Page 149 MEDICINAL......Page 162 INDUSTRIAL......Page 163 SCIENTIFIC......Page 164 HISTORICAL BACKGROUND......Page 165 UNITS FOR MEASURING IONIZING RADIATION......Page 168 SOURCES AND LEVELS OF RADIATION IN THE ENVIRONMENT......Page 169 ARTIFICIAL SOURCES......Page 172 MECHANISM OF BIOLOGIC ACTION......Page 175 RADIONUCLIDES AND RADIOACTIVE FALLOUT......Page 177 ACCUMULATION IN CRITICAL ORGANS......Page 178 THE HAZARDS OF LONG-LIVED RADIOISOTOPES......Page 180 MAJOR TYPES OF RADIATION INJURY......Page 182 EFFECTS ON THE CELL......Page 183 EFFECTS ON ORGANS OF THE BODY (SOMATIC EFFECTS)......Page 189 EFFECTS ON THE GROWTH AND DEVELOPMENT OF THE EMBRYO......Page 195 EFFECTS ON THE INCIDENCE OF CANCER......Page 196 PROTECTION AGAINST EXTERNAL RADIATION......Page 200 CONTROL OF RADIATION RISKS......Page 202 CHAPTER 6 NUCLEAR FISSION......Page 205 HISTORY OF FISSION RESEARCH AND TECHNOLOGY......Page 206 STRUCTURE AND STABILITY OF NUCLEAR MATTER......Page 209 INDUCED FISSION......Page 212 SPONTANEOUS FISSION......Page 213 THE PHENOMENOLOGY OF FISSION......Page 214 FISSION FRAGMENT MASS DISTRIBUTIONS......Page 216 FISSION DECAY CHAINS AND CHARGE DISTRIBUTION......Page 218 PROMPT NEUTRONS IN FISSION......Page 220 DELAYED NEUTRONS IN FISSION......Page 221 ENERGY RELEASE IN FISSION......Page 222 FISSION THEORY......Page 223 NUCLEAR MODELS AND NUCLEAR FISSION......Page 225 FISSION CHAIN REACTIONS AND THEIR CONTROL......Page 235 USES OF FISSION REACTORS AND FISSION PRODUCTS......Page 237 THE FUSION REACTION......Page 238 TWO TYPES OF FUSION REACTIONS......Page 239 ENERGY RELEASED IN FUSION REACTIONS......Page 241 RATE AND YIELD OF FUSION REACTIONS......Page 242 THE PLASMA STATE......Page 244 FUSION REACTIONS IN STARS......Page 246 FUSION REACTIONS FOR CONTROLLED POWER GENERATION......Page 248 MAGNETIC CONFINEMENT......Page 249 INERTIAL CONFINEMENT FUSION (ICF)......Page 252 MUON-CATALYZED FUSION......Page 254 COLD FUSION AND BUBBLE FUSION......Page 255 CONDITIONS FOR PRACTICAL FUSION YIELD......Page 256 HISTORY OF FUSION ENERGY RESEARCH......Page 258 CONCLUSION......Page 260 DEMOCRITUS......Page 263 18TH AND 19TH CENTURIES: BEGINNINGS OF ATOMIC THEORY......Page 266 AMEDEO AVOGADRO......Page 267 JOHANN JAKOB BALMER......Page 270 JÖNS JACOB BERZELIUS......Page 271 ROBERT BROWN......Page 274 ROBERT WILHELM BUNSEN......Page 276 STANISLAO CANNIZZARO......Page 278 JOHN DALTON......Page 281 JOSEPH LOSCHMIDT......Page 285 DMITRY IVANOVICH MENDELEYEV......Page 286 LOTHAR MEYER......Page 289 JEAN PERRIN......Page 290 JOSEPH-LOUIS PROUST......Page 291 20TH CENTURY: RADIATION AND AFTER......Page 295 HENRI BECQUEREL......Page 296 MARIE CURIE......Page 299 PIERRE CURIE......Page 304 OTTO HAHN......Page 307 HENRY GWYN JEFFREYS MOSELEY......Page 310 WILHELM RÖNTGEN......Page 311 ERNEST RUTHERFORD......Page 312 FREDERICK SODDY......Page 316 FRITZ STRASSMANN......Page 317 SIR J.J. THOMSON......Page 318 GLOSSARY......Page 322 ATOMIC COMPONENTS AND PROPERTIES......Page 326 RADIOACTIVITY......Page 327 NUCLEAR FISSION......Page 328 NUCLEAR FUSION......Page 329 RADIATION......Page 330 INDEX......Page 335