1. Naming Molecules Section 9.2
Chemistry

2. Objectives
Identify the names of binary molecular compounds from their formulas.

3. Analogies
The millions of compounds in the world and crayons in the Crayola® box

4. Naming Binary Molecular Compounds
binary: a molecule that contains only two different elements.
do not contain metals or ions
Do contain two different nonmetals

5. 3 Rules for Naming Binary Compounds
The first element in the formula is always named first, using the entire element name.
The second element in the formula is named using the root of the element and adding the suffix –ide.

6. 3 Rules for Naming Binary Compounds Cont.
Prefixes are used to indicate the number of atoms of each type that are present in the compound.
Prefixes are similar to the ones used in geometry in naming polygons.

7. Prefixes for Molecular Compounds1 2
One – mono-
Two – di-
Three – tri-
Four – tetra-
Five – penta- 3 4 5

8. Prefixes for Molecular Compounds Cont.6
Six – hexa-
Seven – hepta-
Eight – octa-
Nine – nona-
Ten – deca- 7 8 9 10

9. Prefixes for Molecular Compounds Cont.
One exception is that the first element in the formula never uses the prefix mono-.
Ex: CO
Incorrect: Monocarbon monooxide.
Correct: Carbon monooxide.

10. Example Problems
Page 249
13-17

11. Common Names of Compounds
Many binary compounds were discovered and given common names long before the modern naming system was developed.
Examples: Page 249, table 9-2.

12. Formulas and Names of Some Covalent Compounds

13. Naming Acid
Water solutions of some molecules are acidic and are named as acids
If the compound produces hydrogen ions in solution, it is an acid.

14. Naming Binary Acids
A Binary Acid contains hydrogen and another element.
When naming a binary acid , use the prefix hydro- to name the hydrogen part of the compound,
The second element use the root name and the suffix -ic.
Example: HBr

15. Naming Oxyacids
Any acid that contains hydrogen and an oxyanion is referred to as a oxyacid.
Remember an oxyanion is a polyatomic ion that contains an oxygen atom

16. Rules for Naming Oxyacids
Name depends on the oxyanion present
The name of an oxyacid consists of a form of the root of the anion, a suffix , and the word acid
If the oxyanion ends in –ate , it is replaced by –ic
If the oxyanion ends in –ite, it is replaced by –ous

17. Examples
HNO3
HNO2

18. Practice Problems
Page 250

19. Writing Formulas from Names
Subscripts are determined by prefixes
Example: Dihydrogen monoxide

20. Homework
23-29 on page 251