Chapter Overview
Everything around us is made up of atoms and molecules. This chapter explores the fundamental concepts of atoms, molecules, laws of chemical combination, atomic mass, and molecular mass. It also explains how elements combine in fixed ratios to form compounds and introduces key scientific principles such as Dalton’s Atomic Theory and Avogadro’s Hypothesis.
Important Keywords
- Atom: The smallest unit of an element that retains its properties.
- Molecule: A group of atoms chemically bonded together.
- Atomic Mass Unit (amu): A unit used to express atomic and molecular masses.
- Molecular Mass: The sum of the atomic masses of all atoms in a molecule.
- Law of Conservation of Mass: Mass can neither be created nor destroyed in a chemical reaction.
- Law of Constant Proportion: A given compound always contains the same elements in the same proportion by mass.
- Dalton’s Atomic Theory: A theory stating that atoms are indivisible and combine in simple whole-number ratios.
- Avogadro’s Number (6.022 × 10²³): The number of atoms or molecules in one mole of a substance.