Necessity is the mother of invention. Human curiosity and imagination had added a wing to our flight of invention. Science has no destination but journey. As a domain of science chemistry also deals with what? Why? How? From what the matter around us made up of? And what are the properties of these matters? These are the subjects of chemistry. It has a golden history from alchemists to the detection of higgs boson (commonly referred by journalists "the god particle"). It is assumed that alchemists used to convert other elements into gold. Now we are observing the same thing only the difference between two elements is the number of fundamental particles electron, proton, and neutrons. Now, we are aware of that the whole universe is made up of 118 elements (discovered till now). Our body, the daily items we use, medicine we take, and our surroundings all are the result of these elements only. Preface This book is genuinely written for grasping the fundamental concept of chemistry. It is aimed to the secondary level students. It can serve as a reference for a particular topic. It is also useful for various competitions. Index PART 1 1. Structure of Atom 2. Atom and Molecules 3. Matter 4. Pure and Impure Matter PART 2 5. Chemical Reactions and Equations 6. Acid, Base and Salt 7. Metal and Non-Metals 8. Carbon and Its Compounds 9. Periodic Classification of Elements