1. Elements, Compounds, Mixtures….a little review

2. Elements
Pure _________; can’t be broken down simpler substances by _________ means
are arranged in order _________(# of p+) on the Periodic Table
each made of one type of _________
Look around the room for some!
Aluminum (Al), Argon (Ar), Zinc (Zn), Nitrogen (N), Carbon (C), Gold (Au)

3. Hydrogen is the simplest element and makes up over 90% of all matter our universe!

4. Compounds
Pure substance composed of atoms of two or more _____________
Ex. water (H2O), ________________, table salt (NaCl)
_____________________ by physical means; can only be separated by chemical means
Held together by ______________(ionic, covalent, metallic, etc.)

5. Why form compounds?
Atoms like to be stable and happy; they want full _________________
Some atoms have full shells and are already happy being alone (__________- He, Ar, Ne, etc.)
___________don’t have full shells- they fill their shells by combining with other types of atoms Na +1 + Cl -1  NaCl 

6. Molecule The ______________________that can exist Some examples:
Water H2O
Carbon monoxide CO
Hydrochloric acid HCl

7. How do compounds combine and/or break down?
By a chemical reaction (substance is changed into something else)- this causes a chemical change in the substance
Ex. Hydrogen and Oxygen combine to form water 2H2 + O2  2H2O
Another example is rust:
4Fe + 3O2  2Fe2O3

8. Mixtures
Combo of two or more substances; not pure; are ________ but not ___________combined
May be separated by _______means- evaporation, filtration, magnets, picking out pieces, etc.
Exist in any phase- liquids (ethanol & gas); liquid/gas (Coke®); solids (taco salad); gas/solid (smoke)

9. Heterogeneous mixture
-_____________________; “least mixed”
-___________particles
-___________to separate
-examples: salad dressing, your sock drawer, cereal

10. Homogeneous mixture -have a __________________________
A.K.A. solutions ex. saltwater, bronze, air,
mixed ___________
particles are ___________distributed

11. Physical changes
Physical change- may involve a change in state (ex. solid to liquid), or change in size, shape
Examples of physical changes are filtering, evaporation, ripping paper, melting, dissolving
The makeup of the object is unchanged (ex. ripped paper is still paper)

12. Chemical Changes
Chemical change- new substance is formed; products are different from the reactants
Ex. of chemical changes are: burning, dissolving w/ acid, rusting, passing an electrical current through something