1. Warm-up
Pick up your graded Intermolecular Forces POGIL and Practice sheet. Check your answers to the Practice.
a) between hexane and decane (bp=98°C) b) lower than 1-propanol (bp=78°C) c) between 2-hexane and 2-decane (bp=173°C)
The cis compound has the higher bp because it has dipole-dipole forces
a) He < CH4 < CH3F < NH b) Ne < CH3Br < CH3CN < CH3OH c) CH4 <SiH4 <GeH4 < SnH4 (all nonpolar, increased MW increases dispersion forces)
O-H bond is a covalent bond where electrons are shared. Hydrogen bond I an attraction.
CH3OH can hydrogen bond, which is the strongest IMF

2. Extra Credit: Should draw a structure with two OH groups that would allow for two hydrogen bonds,
a) CH3CH2CH2NH2 (it can hydrogen bond!) b) NaCl (ionic compound) c) CaO (ionic compound; 2+/2-)
CH3C=OCH3 (second answer choice)
C-strongest covalent bond because F has the smallest atomic radius due to a large Zeff

3. Warm-up
Rank the types of intermolecular forces in terms of strength, starting with the weakest and ending with the strongest.

4. Unit 7 Review

5. Topics to Study
Properties of Chemical Bonds/Intramolecular Forces (Covalent, Ionic, Metalic)
How do they form?; Conduct heat/electricity?; brittle or not?; relative bp/mp?; etc.
Molecule vs. Formula Unit
Intermolecular Forces (Ion-Dipole, Hydrogen “Bonding”, Dipole-Dipole, Dispersion)
When do they form?; Relative strength; Identify the forces that exist between given molecules; Rank molecules based on bp

6. Metallic Properties
Delocalized sea of electrons explains several properties of metals:
Good conductors of heat
Good conductors of electricity
Ductile
Malleable
Strong
High melting and boiling points

7. Ionic Properties Formula unit Very high melting points
Brittle crystalline structures
Soluble in water
Good conductors of electricity IF melted or dissolved

8. Covalent Properties Molecule Low melting and boiling points
Many are liquids and gases at room temperature
Soluble in water IF they are polar (like dissolves like)
Do not conduct electricity

9. Drawing/Identifying Lewis Structures
Calculate ΔEN (know the ranges for ionic/polar/nonpolar)
Dipole arrows (partial positive and partial negative)
Polar or Nonpolar?
Geometric Shapes
Bond Strength
Lattice Energy (Ionic)
Charges, then size
Covalent
Single/Double/Triple
Then, Size
“Like Dissolves Like”