1. Compound Names and Formulas
Section 4.3

2. Naming Compounds Each compound has a unique name
Relatively easy rules for naming ionic and covalent compounds

3. Naming Ionic Compounds
Name of cation stays the same
Lithium atom  lithium (ion)
Magnesium atom  magnesium (ion)
Name of anion turns into an “ide”
Chlorine atom  chloride (ion)
Iodine atom  iodide (ion)
Name = cation + anion
Lithium + Chlorine  Lithium Chloride

4. More examples of ionic compounds
Barium Chloride
Magnesium Bromide
Sodium Sulfide
Cesium Nitride
Rubidium Oxide
Lithium Fluoride
Potassium Chloride

5. Predicting the number of cations & anions in an ionic compound
Example: Magnesium Fluoride
Magnesium cation has a +2 charge
Fluoride has a -1 charge
Mg2+F-1
Rule: Erase charges, replace superscripts with subscripts and switch the numbers between the ions

6. Example: 2+ 2 1- 1 Mg F

7. Why? -1 -1 2+ Magnesium cation: +2 charge Fluoride anion: -1 charge
It takes TWO fluoride ions to cancel out the charge of the magnesium cation. -1 -1 2+

8. Example #2: -2 -2 -2 3+ 3+ 3 2- 2 Al O 3+
It takes 2 aluminum ions and 3 oxide ions to cancel out the charges!

9. Example #3: -2 2+ 2+ 2 2- 2 Ca S
Since the charges are equal, it only takes one of each to make the compound neutral!

10. Ionic bonds with transition metals
Many transition metals can take on more than one charge as an ion:
Cu+, Cu2+
Fe2+, Fe3+
If Cu+ bonds to F-, you get CuF
If Cu2+ bonds to F-, you get CuF2
Both cannot be called “Copper Fluoride”
What can we do?

11. The answer!
Designate the charge of the cation in the name by using Roman numerals!
CuF contains a copper cation of charge +1
We call this Copper (I) Fluoride
CuF2 contains a copper cation of charge +2
We call this Copper (II) Fluoride
Rule: When working with transition metals, put the charge of the cation in parentheses using Roman numerals!

13. Naming Covalent Compounds
Let’s look at one we already know:
Carbon Dioxide (CO2)
The first element is named regularly (carbon)
The second element gets an “-ide”
The number of each element is represented by a prefix.
Rule: If there is only one atom of the first element, it does not get a prefix.
Otherwise, the first and second elements get prefixes according to the following table:

14. Table of prefixes Number of Atoms Prefix 1 Mono- 2 Di- 3 Tri- 4 Tetra-5
Penta- 6
Hexa- 7
Hepta- 8
Octa- 9
Nona- 10
Deca-

15. Examples H2O N2O4 P4S3 SiI4 PCl3 P4O10 Number of Atoms Prefix 1 Mono-
Di- 3
Tri- 4
Tetra- 5
Penta- 6
Hexa- 7
Hepta- 8
Octa- 9
Nona- 10
Deca-
H2O
N2O4
P4S3
SiI4
PCl3
P4O10

16. Remember the Name Chemistry Remix
Follow along with the lyrics on the back of your HRL