1. Aim: How can we name a compound?
Do Now:
Take out a calculator and reference tables.
What is the percent composition of the elements in the compound CaCl2?

2. How can we figure out the name of CaCl2?
Compounds are named according to the types of elements that form them.
The name of the compound depends on whether the compound is ionic or covalent.

3. How to name ionic compounds
Binary ionic compounds (only two elements) come from the name of the elements in the compound.
The compound name will start with the positive ion first.
Example: CaCl2 starts with the name
The name of the negative ion is changed to end with the suffix –ide.
Example: CaCl2 ends with
So, the total name of CaCl2 is

4. Some Practice Naming Binary Compounds
Name the following compounds:
MgS
AlF3
CaO

5. Some More Practice Naming
Write the chemical formula for the following compounds:
Lithium flouride
Aluminum oxide
Beryllium chloride

6. Naming Compounds with Polyatomic Ions
When the positive ion is a metal, start the name with that metal.
Add the name of the negative polyatomic ion.
Example: KNO3
Example: CaCr2O7

7. What if the positive ion is polyatomic?
If the positive ion is polyatomic, we start the name with that ion.
If the negative ion is a nonmetal, we end the name with the name of that element ending in ide.
If the negative ion is polyatomic, it retains its name.
Example: NH4Cl
Example: NH4NO3

8. What if we are naming covalent compounds?
The order in which the elements are written in a binary compound depends on their electronegativity. The element with the lower electronegativity is written first.
Example: A carbon atom bonds with an oxygen atom. The carbon’s electronegativity is ______ and the oxygen’s electronegativity is _______.
So, we start the name of the compound with ___________ and end it with ________ changed to ide ending. So, the name of this compound would be…

9. What if there is more than one atom of a particular element in a binary compound?
A prefix is used to show how many atoms are in the compound.
Number of Atoms
Prefix

10. Name the following binary molecular compounds.
Examples
Name the following binary molecular compounds.
SiF4
N2O4
S4N4
H2S

11. How do we name a formula whose metal has more than one oxidation state?
We use what’s called the stock system. The stock system changes whichever oxidation state the metal was in to a roman numeral.
Example: When iron bonds with chlorine to form FeCl2 it has an oxidation state of +2. So we write the formula as
If the iron forms FeCl3, then it has an oxidation state of +3. So we write the formula as

12. Activity/ Homework
Copy and answer questions on page 33 of your review book.