Preface<br > The ninth edition of College Chemistry reflects another<br > thorough revision. To keep up with progress in modern chem-<br > istry， some of the less important chapters have been deleted and<br > others have been rearranged or combined. The chapters on<br > atomic structure and the periodic classification of the elements<br > have been revised so completely that they are， essentially， new<br > material. A new chapter on the chemical bond has also been<br > added. The revised book contains a number of important new<br > tables， graphs， and figures that will be very useful to students and<br > others. The appendixes have been enlarged to include (I) an<br > activity table of the metals and (2) a table containing the elec-<br > tronic populations of atoms.<br > This new edition， like the earlier ones， summarizes the chem-<br > istry found in the latest editions of the most widely used general<br > chemistry texts and also new texts that have recently come on the<br > market. And， like the earlier editions， this new College Chemistry<br > may be used as a textbook.<br > The author and publishers are grateful to students and others<br > who have written to them concerning earlier editions. It is to be<br >i hoped that comments and suggestions regarding the ninth edition<br > will also be forthcoming.<br > The author wishes to thank Dr. Gladys Walterhouse， Editor，<br > of Barnes and Noble， Inc. for her excellent work in editing this<br >i i book. It has been markedly improved through her valuable<br > suggestions.<br > I wish to thank Mrs. Iris Adams for the careful work she did in<br >i~ typing part of the manuscript. My thanks are also due to Mrs.<br > Dawn Ann Bailey for stenographic work and especially for the<br >~:~i many courtesies she extended to the author. They made his tasks<br >~ ~，~ Finally great credit and appreciation are due my wife， Hazel，<br >~ for the careful work she did in preparing the Index.<br >