1. Unit 6 Notes – Chapters 4 & 12
Mr Nelson 2009

2. Ionic Compounds – Review
Made up of ions
Cations (+) & Anions (-)
Metals & Nonmetals (or polyatomic ions)
Exchange of electrons
Charges Balance

3. Molecular Compounds – Intro
No ions
Charges will not balance
Composed of two nonmetals
Sharing of electrons
Covalent bonding
Naming is based on prefixes

4. Nomenclature of Binary Compounds
If both elements are nonmetals we must use prefixes.
The 1st element only gets a prefix if it is greater than 1.
2nd element always gets a prefix and change the ending to -ide

5. Nomenclature of Binary Compounds
Example of a molecular comp:
CO2 CO
CCl4

6. Nomenclature of Binary Compounds
If the prefix ends with a or o and the name of the element begins with a vowel, the two successive vowels are combined into one.
N2O5: dinitrogen pentoxide

7. Practice PCl5 dihydrogen monoxide SF6 carbon trichloride
N2O disulfur hexoxide
NO2 nitrogen triiodide

8. Naming Acids An acid is any compound that starts with a hydrogen
When naming an acid:
1st locate the anion (- charge)

9. Acid Nomenclature
If the anion in the acid ends in -ide, change the ending to -ic acid and add the prefix hydro- .
HCl: hydrochloric acid
HBr: hydrobromic acid

10. Acid Nomenclature
If the anion in the acid ends in -ite, change the ending to -ous acid.
HClO: hypochlorous acid
HClO2: chlorous acid

11. Acid Nomenclature
If the anion in the acid ends in -ate, change the ending to -ic acid.
HClO3: chloric acid
HClO4: perchloric acid

12. Warm Up HBr Chlorous Acid FeS Copper(I) fluoride
PBr5 dinitrogen dioxide
KSO4 nitrogen monoxide
CCl4 hydroiodic acid
HNO3 potassium nitrate
LiCl phosphoric acid

13. Lewis Dot Structures ONLY Valence (outer) electrons are involved.
You can do Lewis dot structures for atoms and for compounds
Lewis dot structures tell you the structure of a molecule of a compound, help predict shape.

14. Lewis Dot Structure Example
Example: Bromine
Number of valence electrons _____

15. Steps to Writing Lewis Structures
Find the sum of valence electrons of all atoms in the polyatomic ion or molecule.
PCl3
(7) = 26

16. Writing Lewis Structures
Arrange element symbols to show how atoms are connected – show electrons as dots.
Draw in the valence electrons of each of the atoms
Keep track of the electrons:

17. Writing Lewis Structures
Connect the lines to form single bonds.
1 line = 2 electrons
Keep track of the electrons:

18. Writing Lewis Structures
Finish by checking for octets.
Hydrogen only needs 2 electrons to be happy
Keep track of the electrons:

19. Writing Lewis Structures
If the central atom does not have an octet…
…form multiple bonds until it does. Example: HCN

20. Exceptions!
Boron and Aluminum are okay with only 6 valence electrons around it
BF3

21. Exceptions If the Lewis Dot Structure you are drawing is an ion:
Use [] and specify the charge
Add or subtract electrons
Positive charges take away electrons
Negative charges add electrons
Example: Br-