1. Elements, Compounds, and Mixtures
Notes

2. How is Matter Classified?
Pure substance
One type of material
One set of physical and chemical properties
Cannot be physically separated
Elements
Compounds
Mixture
Two or more substances that are not chemically combined
Can be physically separated
Heterogeneous
Homogeneous

3. Elements
Pure substance
Cannot be broken down
Made of one type of atom
Building blocks of matter
Representation
Periodic Table of Elements
Organized according to their properties
Represented by a symbol
ONE capital letter (first letter)
Other letters are lower case
No periods (Ex: O, Ca, Fe, N)

4. Compounds
Pure substance
Two or more elements that have been chemically combined (chemical reaction)
Cannot be broken down physically
Representation
Chemical formulas (combination of the elements that make up that compound)
More than one capital letter (Ex: NaCl, H2O)

5. Mixtures
Two or more pure substances that are physically combined, NOT chemically
Can be physically separated
Two types
Homogeneous
Same appearance and composition throughout
Examples: vinegar, lemonade
Heterogeneous
You can see the separate substances
Examples: oil and water, salad

6. Molecule
Made of two or more atoms that have combined chemically
Can be two or more of the same atom (element); Example: O2, H2
Can be two or more different elements (compound); Example: CO, H2O