1. Do Now: What do the following things have in common
Do Now: What do the following things have in common? What is the benefit to using them?
BRB
ROTFL
SMH
LOL
GR8 UR
XOXO JK

2. Using Symbols and Formulas
TO DESCRIBE MATTER

3. Symbols – represent an element
Elements are represented using a 1 or 2 letter symbol
The first letter MUST be capitalized, and the second must be lowercase
Example: H = hydrogen, He = helium

4. Formulas – represent a molecule
Made up of symbols and subscripts
Symbols tell you what element(s) are in the molecule
Subscripts tell you how many of each element make up the molecule (no subscript = only one atom of that element)
Ex/ H2O
subscript

5. Example: CH4 C = Carbon – 1 H = Hydrogen – 4 AgNO3 Ag = Silver – 1
N = Nitrogen – 1
O = Oxygen - 3

6. Practice
K2CO3
FeCO3
NaNO2
Na2SO4
NaHSO4

7. Honors: Parentheses
A polyatomic ion is a group of two or more atoms bonded together that then bond to another atom/group as a unit.
If there are more than one of these units bonded in a compound they are contained within parentheses and a subscript is used. The subscript is distributed to all of the elements in the polyatomic ion.
Ex/ Ca(NO3)2
Ca = 1
N = 1 x 2 = 2
O = 3 x 2 = 6