CHEMISTRY CLASS NOTES 11TH STD

Basic concepts of chemistry provide the foundation for understanding chemical phenomena. Chemistry studies matter, its properties, and transformations. Matter is classified into pure substances (elements and compounds) and mixtures (homogeneous and heterogeneous). Atoms, the smallest units of matter, consist of protons, neutrons, and electrons. Elements are defined by their atomic number, while isotopes have the same atomic number but different mass numbers. The periodic table organizes elements based on properties. Chemical reactions involve the rearrangement of atoms, conserving mass. Key principles include atomic theory, stoichiometry, and the mole concept, which links macroscopic quantities to atomic-scale measurements. Understanding these basics is crucial for exploring advanced topics.