1. Chemical Symbols
Show the atoms of the elements composing the substance
Written with 1, 2, or 3 letters
First letter = ALWAYS CAPITALIZED
The rest are lowercase
Each element has a different symbol

2. Elements are made up of ONE kind of atom
Compounds are made up of MORE THAN ONE element & their formulas have more than one type of symbol

3. Chemical Formulas
Constructed from the symbols of the elements composing the substances
Subscripts
Show how many of each kind of atom are in a compound
Written to the lower right of the element symbol
If no subscript is written, only one atom of that element is part of the compound

4. Compounds to Memorize NaCl – salt H2O – water O2 – oxygen gas
CO2 – carbon dioxide
N2 – nitrogen gas
C6H12O6 – simple sugar (glucose)