1. Chapter 9 Notes
Mr Nelson 2009

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

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

4. Acid Nomenclature If the anion in the acid ends in –ide (not PI)
change the ending to -ic acid and add the prefix hydro-
hydro________ic acid
HCl: hydrochloric acid

5. Acid Nomenclature If the anion in the acid ends in –ite (all PI’s)
change the ending to -ous acid.
_________ous acid
HClO2: chlorous acid

6. Acid Nomenclature If the anion in the acid ends in –ate (all Pi’s)
change the ending to -ic acid.
___________ic acid
HClO3: chloric acid I

7. Acids – Finishing Up If you have the name and need to find the formula
Example: Acetic Acid
Cross off the –ic and add at –ate
Acetate! = C2H3O2-
Finish by adding the correct # of H’s (1 for every negative)
HC2H3O2 is acetic acid 

8. Covalent Bonding Covalent bond – atoms share electrons.
There are several electrostatic interactions in these bonds:
Attractions between electrons and nuclei
Repulsions between electrons
Repulsions between nuclei

9. Lewis Dot Structures ONLY Valence (outer) electrons are involved.
Lewis dot structures can be drawn for:
atoms
molecules
Lewis dot structures show structure of a molecule, and help predict shape.

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

11. Writing Lewis Structures
Arrange element symbols to show how atoms are connected – show electrons as dots.
Follow the octet rule
except for hydrogen, which only needs two electrons to be full
Connect the electrons as lines
Keep track of the electrons:
= 20

12. Writing Lewis Structures
Fill the octets of the outer atoms.
Keep track of the electrons:
= 20; = 2

13. Writing Lewis Structures
Fill the octet of the central atom.
Finish by checking for octets.
Keep track of the electrons:
= 20; = 2; = 0

14. Writing Lewis Structures
If you run out of electrons before the central atom has an octet…
…form multiple bonds until it does.

15. Exceptions!
Boron and Aluminum are okay with only 6 e- around them
BF3

16. 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-