"Salters' Advanced Chemistry" is a course for 16- to 19-year-olds using a fully-approved A level syllabus administered by the Oxford and Cambridge Board. It aims to show students that the subject is worth studying in its own right, has vocational relevance, and can be enjoyable without compromising academic standards. The course attempts to convey the excitement of contemporary chemistry, exploring the frontiers of chemical research and development and placing chemistry in the context of its practical applications. It has been tested in a variety of schools and colleges. One of four titles in the series, "Chemical Ideas" explains major chemical concepts essential to an understanding of the material presented in its companion volume "Chemical Storylines". Designed to be readily accesible to students, it forms a reference and revision guide to the major concepts needed in A level chemistry, and includes a wide range of problems for students to answer.