1. Warm-Up
Name one physical change and one chemical change that can happen to a book.
Complete sentences!
DON’T TURN IN YESTERDAY’S WORKSHEET!

2. Agenda Review Physical and Chemical properties worksheet Collect WS
Safety Video:
Identify unsafe behaviors
Lab Safety Questions (quiz Thursday)
Notes: Elements and Compounds
HW: Elements and compound naming

3. Elements & Compounds

4. Elements Pure substance One kind of atom 118 elements
91 exist naturally
27 are synthetic (manmade), most of which are radioactive
Cannot be chemically broken down

5. Element Symbols All can be found in the Periodic Table
Some elements are diatomic molecules in their natural state, meaning they contain 2 atoms.
H2, F2, Cl2, Br2, I2 Cu Ag Au Ne N2 O2 Ca Al

6. Compounds Pure substance
Molecules that contain 2 or more different elements
Can be chemically broken down
Properties are vastly different than the properties of the elements that make it up
H2O
C12H22O11
C2H5OH
NaCl

7. Compound Formulas Subscript – gives the number of atoms of each
element in the compound
Practice:
HCl Na3PO Ba(OH)2
Al2(SO4)3 (NH4)2Cr2O7 CH3COOH

8. Compound Formulas H2O H2O2
Changing the ratio of atoms in a specific compound forms a new compound with completely different properties.
H2O
H2O2
Water
Clear & colorless
Necessary for life
Boiling point = 100oC
Density = 1 g/mL
Hydrogen peroxide
Clear & colorless
Toxic if ingested
Boiling point = 150oC
Density = 1.11 g/mL