1. Chapter 5: Soap

2. Introductory Activity
Fill a test tube with an inch of water
Add a squirt of cooking oil to the test tube. Observe
Stopper, shake & observe
Add a few drops of soap. Observe
With another test tube, add water & soap only. Observe.
Compare the two test tubes.
Make particle visualizations describing each test tube.

3. Introductory Activity
What ideas do you have about how soap works?
What kinds of things do advertising and marketing tell you?
What do the soap companies want you to know about how soap works?

4. Soap
This chapter will introduce the chemistry needed to understand how soap works
Section 5.1: Types of bonds
Section 5.2: Drawing Molecules
Section 5.3: Compounds in 3D
Section 5.4: Polarity of Molecules
Section 5.5: Intermolecular Forces
Section 5.6: Intermolecular Forces and Properties

5. Inter-molecular forces Bonding types & Structures
Soap
Works based on
Inter-molecular forces
Determined by
Molecular Geometry
Determined by
Bonding types & Structures

6. Section 5.1—Types of Bonds

7. Why atoms bond
Atoms are most stable when they’re outer shell of electrons is full
Atoms bonds to fill this outer shell
For most atoms, this means having 8 electrons in their valence shell
Called the Octet Rule
Common exceptions are Hydrogen and Helium which can only hold 2 electrons.

8. One way valence shells become full- - - - - - - - - - - - - Na - Cl - - - - - - - - - - - - - -
Sodium has 1 electron in it’s valence shell
Chlorine has 7 electrons in it’s valence shell
Some atoms give electrons away to reveal a full level underneath.
Some atoms gain electrons to fill their current valence shell.

9. One way valence shells become full- - - + - - - - - - - - - - - Na - Cl - - - - - - - - - - - - - -
The sodium now is a cation (positive charge) and the chlorine is now an anion (negative charge).
These opposite charges are now attracted, which is an ionic bond.

10. Ionic Bonding—Metal + Non-metal
Metals have fewer valence electrons and much lower ionization energies (energy needed to remove an electron) than non-metals
Therefore, metals tend to lose their electrons and non-metals gain electrons
Metals become cations (positively charged)
Non-metals become anions (negatively charged)
The cation & anion are attracted because of their charges—forming an ionic bond

11. Bonding between non-metals
When two non-metals bond, neither one loses or gains electrons much more easily than the other one.
Therefore, they share electrons
Non-metals that share electrons evenly form non-polar covalent bonds
Non-metals that share electrons un-evenly form polar covalent bonds

12. Metals bonding
Metals form a pool of electrons that they share together.
The electrons are free to move throughout the structure—like a sea of electrons
Atoms aren’t bonded to specific other atoms, but rather to the network as a whole

13. Bond type affects properties
The type of bonding affects the properties of the substance.
There are always exceptions to these generalizations (especially for very small or very big molecules), but overall the pattern is correct

14. Melting/Boiling Points
Ionic bonds tend to have very high melting/boiling points as it’s hard to pull apart those electrostatic attractions
They’re found as solids under normal conditions
Polar covalent bonds have the next highest melting/boiling points
Most are solids or liquids under normal conditions
Non-polar covalent bonds have lower melting/boiling points
Most are found as liquids or gases

15. Solubility in Water
Ionic & polar covalent compounds tend to be soluble in water
Non-polar & metallic compounds tend to be insoluble

16. Conductivity of Electricity
In order to conduct electricity, charge must be able to move or flow
Metallic bonds have free-moving electrons—they can conduct electricity in solid and liquid state
Ionic bonds have free-floating ions when dissolved in water or in liquid form that allow them conduct electricity
Covalent bonds never have charges free to move and therefore cannot conduct electricity in any situation