The Zimbabwe Secondary School Science Project (ZIM-SCI) developed student study guides, corresponding teaching guides, and science kits for a low-cost science course which could be taught during the third year of secondary school without the aid of qualified teachers and conventional laboratories. This teaching guide, designed to be used in conjunction with the related student guide, includes instructional strategies, lists of required materials, laboratory procedures, and other information for a four-part unit which expands on the concepts about particles learned in ZIM-SCI units C1 ("What is Water?") and C2 ("Particles in Action"). Activities and experiments focus on: (1) elements, compounds, and mixtures; (2) particulate structure of matter and Brownian motion; (3) electrostatics and ions; and (4) chemical bonding. Since concepts in this unit cover requirements of the O-Level General Science Syllabus Examination, actual O-level examination questions are included. Each section in this guide corresponds to a given section in the student study guide. (JN)