1. VSEPR theory Bond Polarity Intermolecular Forces Nomenclature
8.1,8.2, 8.3, 8.4 and 9.3
VSEPR theory
Bond Polarity
Intermolecular Forces
Nomenclature

2. Review of Molecular compounds covalent bonding (video)
Molecular (covalent) compounds share e-.
Recognize by NM/NM ex: PCl3
Diatomic Elements are covalent (scared 7)
H2, N2, O2, F2, Cl2, Br2, I2
Biological mc (mc=molecule) are covalent

3. Octet Rule/Lewis Dot structures
Octet Rule: all molecular compounds share e- so each element obtains a noble gas config. (8e-)
Lewis Dot Structure (LDS): visual representation of covalent bonds showing the octet rule. Each element has 8 dots (except H)

4. Rules for LDS All atoms have octet (except H- only 2)
Usually have 1 center atom (the others come off of it)(C loves to be the center of attention)
Cannot add/subtract electrons for fun
Try for symmetry.
Single bonds (2 e-), double bonds (4 e-) triple bonds (6 e-)

5. LDS example Lewis Dot structures (video)
1 Carbon
2 Fluorine
Combine
To form
CF4

6. VSEPR THEORY Valence Shell Electron Pair Repulsion Theory
Pairs of e- will push away from each other to be as far apart as possible
This creates shapes
Tetrahedral, pyramidal, bent

7. Bond Polarity
Nonpolar Bond: electrons are evenly shared between atoms.
Polar Bond: electrons are shared unevenly between atoms creating a slightly +/- situation

8. How do you tell if a bond is P or NP? Polarity (video)
Subtract electronegativites of atoms and if difference is:
Do not memorize e-neg (pg. 177)
Greater than 1.5
Ionic
Less than .5
Nonpolar (NP)
Greater than .5
Polar
Example: water (H and O): = 1.4 P
Example: methane (C and H) – 2.1 = .4 NP

10. Intermolecular Forces (IMF)
Molecular Compounds
Ionic Compouds
IMF: attraction between mc
Strength of IMF depends on polarity
Have no IMF, all equally attracted to each other
Very strong

11. 3 types of IMF
Van der Waals or Dispersion: weak attraction between NP mc – electrons are just kind of shared bt mc
Dipole-Dipole: attraction between Polar mc – act like a weak magnet (semi +/- attractions)
Hydrogen Bonding: fairly strong attraction between mc that are polar and have H in it.
(stronger +/- attraction)

12. Dispersion Forces

13. Dipole-dipole interactions

14. Hydrogen Bonding

15. Naming Molecular Compounds
Because molecules can have such varying formulas (ex: CO and CO2), naming is different from Ionic.
When naming you must say how many of each atom you have
1-mono, 2-di, 3-tri, 4-tetra, 5-penta, 6-hexa, 7-hepta, 8-octa, 9-nano, 10-deca
CO2 – carbon dioxide
Mono is optional for first atom

16. Molecular Nomenclature
Writing Molecular Names
Writing Molecular Formulas
Write element name
Second element ends in -ide
Subscripts become Prefixes
1-mono, 2-di, 3-tri, 4-tetra, 5-penta, 6-hexa, 7-hepta, 8-octa, 9-nano, 10-deca
Example: N2O7
Dinitrogen Heptaoxide
Write symbols of elements in compound
Prefixes become subscripts
Ex: Tricarbon tetraphosphide
C3P4