All matter is either pure or a mixture. Pure matter - elements (atoms) or compounds (molecules). Mixtures - homogenous (joined) or heterogeneous (separate). All atoms present before a chemical reaction must be present after. (Law of Conservation of Matter) Chemical formula represents the type and amount of elements that make up the compound – AlCl 3

Properties of Materials

Use the periodic table to differentiate among metals, nonmetals and metalloids Classify elements as metals, nonmetals or metalloids based on their propertaies Describe different types of physical and chemical properties.

Physical propertiesChemical properties MetalloidsLustre Malleability Ductility StateHardness Melting Point Boiling pointViscosity DensitySolubilityCombustible KEY TERMS

Physical properties Traits that can be observed or measured without changing the composition of matter. Used to observe and describe matter.

Examples of Physical Properties: 1. State – solid, liquid or gas at room temperature. 2. Hardness – how difficult it is to scratch or dent. 3. Melting point – unique temperature needed to change from solid into liquid. 4. Boiling point – unique temperature needed to change from liquid into gas.

5. Lustre – shiny or dull. 6. Malleability – how easy to bend or flatten. (opposite – brittle) 7. Ductility – how easy to pull into a wire. 8. Viscosity – how easy it flows or moves. 9. Solubility – does it dissolve in water. 10. Conductivity – will heat/electricity go through.

Same size = same volume. heavier density = mass volume density = mass volume LeadWater 11. Density amount of matter (stuff) in a volume of substance. atoms

Chemical properties Describes how a substance will react with another substance to form new materials. Cannot be observed without changing the original material.

Examples: 1. Combustion – does it burn or ignite when mixed. 2. Corrosion – does it react with acids. 3. Oxidation – does it react with air. 4. Hydration – does it react with water. 5. Heating – does it react to heat. *Don't confuse with boiling – state change/physical.

Metals Most common form of matter – 75% of elements. Metals demonstrate similar (but NOT identical) physical and chemical properties. Non-metals 15% of elements. Non-metals demonstrate properties that are the opposite of metals.

Metalloids: Elements on the staircase – 6% of elements. Exhibit properties between metal and non-metals.

PropertyMetalNonmetalMetalloid Lustre Malleable Ductile State (Rm Tp) Conduct heat Conduct electricity (*) – there are exceptions to these properties shiny solid* dullshiny* solid / gas*solid semi * * *