1. Classification of Matter

• Elements: Pure substances made up of only one type of atom (e.g., Iron, Oxygen, Gold). They cannot be broken down into simpler substances by chemical means.
• Compounds: Pure substances formed when two or more elements combine chemically in a fixed ratio (e.g., Water, Carbon dioxide). They have properties different from their constituent elements.
• Mixtures: Impure substances formed by mixing two or more substances in any proportion. Components retain their individual properties and can be separated by physical methods.

2. Types of Elements

• Metals: Generally hard, lustrous (shiny), malleable (can be beaten into sheets), ductile (drawn into wires), and good conductors of heat/electricity (e.g., Copper, Iron, Gold).
• Non-metals: Generally soft, dull, brittle (break easily), and poor conductors (e.g., Carbon, Oxygen, Sulfur).
• Metalloids: Show properties of both metals and non-metals (e.g., Silicon, Germanium).

3. Symbols and Formulas

• Symbol: Short representation of an element (e.g., H for Hydrogen, Na for Sodium, Fe for Iron).
• Chemical Formula: Representation of a compound showing the number of atoms of each element (e.g., H₂O for Water, CO₂ for Carbon dioxide).
• Atomicity: The number of atoms present in a molecule of an element (e.g., Argon is Monoatomic, Oxygen is Diatomic O₂, Ozone is Triatomic O₃).

4. Separation of Mixtures

Components of a mixture can be separated by physical methods:

• Magnetic Separation: Separating magnetic components (like iron) using a magnet.
• Filtration: Separating insoluble solids from liquids.
• Evaporation: Separating dissolved solids from liquids.
• Winnowing/Sieving: Used for separating grains based on weight or size.