1. ELEMENTS, COMPOUNDS, AND MIXTURES A Meteorite may travel 400 M km to reach Earth. BUT, the particles of iron in a meteorite, a steel spoon and braces are all alike!

2. Elements, the Simplest Substances Element: a pure substance that CANNOT be separated into simpler substances by physical or chemical means. Examples: Iron, Gold, Mercury, Nickel, Cobalt.

3. Elements, the Simplest Substances A pure substance: contains only ONE TYPE of particle. These particles are called ATOMS! Example: Every atoms in a 5 g nugget of gold is like every other atom of gold!

4. Properties of Elements PHYSICAL PROPERTIES : Boiling Point Melting Point Density Texture Color CHEMICAL PROPERTIES: Reactivity with Acid Flammable

5. Identifying Elements by Their Properties Elements can be identified by their properties. Example: Look on page 57 – Figure 2. What element has a Melting Point of 1,535 degrees Celsius and combines slowly with O in the air? ANSWER:_________________

6. Classifying Elements by Their Properties Elements are grouped into categories by the properties they share. 3 Major Categories: METALS: Shiny, good conductors NONMETALS: Dull, poor conductors METALLOIDS: Have properties of both metals and nonmetals!

7. Compounds Compounds : 2 or more elements that are CHEMICALLY combined! They combine through a chemical reaction. In Figure 1: page 60 – Mg + O = MgO Magnesium Oxide (MgO) is a NEW substance with different characteristics!

8. Examples of Compounds Table Salt: NaCl Water: H 2 O Vinegar: CH 3 COOH Carbon Dioxide: CO 2 Baking Soda: NaHCO 3 Sugar: C 12 H 22 O 11

9. Compounds vs Elements COMPOUNDS Salt: a safe seasoning for you to eat. ELEMENTS Sodium: soft, silvery white metal that reacts violently with water. Chlorine: poisonous, greenish yellow gas

10. Breaking Down Compounds Compounds can be broken down into elements or simpler compounds. HOW??? – By Chemical Changes ! Example : Carbonic Acid (gives soda “fizz”) breaks down into Carbon Dioxide and Water just when you open a soda. Carbon Dioxide and Water can be broken down by chemical changes.

11. MIXTURES Mixture : a combination of two or more substances that are NOT chemically combined. NO chemical change happens when a mixture is made. EX: Pizza, Chex Mix, Lucky Charms, Salad.

12. Solutions Solutions : a mixture that appears to be a single substance. It is composed of particles of two or more substances. SOLUTE + SOLVENT = SOLUTION Is Dissolved + Dissolves It Hot Cocoa Mix + Water = Hot Cocoa

13. Concentration of Solutions Concentration: a measure of the amount of solute dissolved in a solvent. Concentrated : TOO much solute Dilute : TOO little solute

14. Suspensions Suspension: a mixture in which particles of a material are dispersed throughout a liquid or gas but are large enough to settle out.

15. Colloids Colloid: a mixture in which the particles are dispersed throughout but are not heavy enough to settle out. The particles in a colloid are much smaller than in a suspension. Examples: Milk, Mayonnaise, Stick Deodorant, and Jello

16. I Can Statements… I can tell you that an element is… I can tell you that a compound is… I can tell you that a solution is… I can tell you that a suspension is… I can tell you that a colloid is…