1. ? ? ? Attractions Intra– Inter– “Bonds” “IMAFs” (strong) (weak) Ionic
(metal–nonmetal)
Covalent
(nonmetals) ? ?
non-polar
polar ?

2. Intermolecular Attractive Forces
IMAF’s
Intramolecular Attraction (within)
(strong bonds)
(weak)
Intermolecular Attraction (between)
Which attraction is overcome (broken) by melting & vaporizing?
weak IMAFs between molecules

3. Intermolecular Attractive Forces
IMAF’s
Intramolecular Attraction (within)
(strong bonds)
(weak)
Intermolecular Attraction (between)
IMAFs determine physical properties:
phase (s, l, g), boiling point, melting point,…

4. ? Attractions Intra– Inter– “Bonds” “IMAFs” (strong) Ionic Covalent
(metal–nonmetal)
Covalent
(nonmetals)
polar
non-polar
Inter–
(weak)
“Bonds”
“IMAFs” ?

5. London Dispersion Forces (LDFs)
temporary dipoles caused by
the motion of e–’s
nonpolar d+ d–

6. London Dispersion Forces (LDFs)
temporary dipoles caused by
the motion of e–’s
weakest IMAF’s
nonpolar d– d+ d– d+ d– d+

7. London dispersion forces
Attractions
Intra–
(strong)
Ionic
(metal–nonmetal)
Covalent
(nonmetals)
polar
non-polar
Inter–
(weak)
“Bonds”
“IMAFs”
London dispersion forces
(nonpolar & all) ?

8. Dipole-Dipole Forces
permanent dipoles from
polar molecules H Cl H Cl

9. London dispersion forces
Attractions
Intra–
(strong)
Ionic
(metal–nonmetal)
Covalent
(nonmetals)
polar
non-polar
Inter–
(weak)
London dispersion forces
(all, nonpolar)
dipole–dipole
(polar)
“Bonds”
“IMAFs” ?

10. d– d+ d– d+ d+ d+ Hydrogen Bonding NH3 H2S
H-bonds are caused by an electron deficient H atoms (bonded to N, O, or F) attracted to small, very electronegative N, O, or F atoms on a nearby molecule.
H-bonds are the strongest IMAF
CH4
CH3F √ HF √
CH3OH

11. London dispersion forces
Attractions
Intra–
(strong)
Ionic
(metal–nonmetal)
Covalent
(nonmetals)
polar
non-polar
Inter–
(weak)
London dispersion forces
(all, nonpolar)
dipole–dipole
(polar)
“Bonds”
“IMAFs”
H–bonds
H with N, O, F

12. (diff electronegativies)
Intermolecular Attractive Forces
H-bonds
(an H bonded to N, O, or F
attracted to nearby N, O, or F)
dipole-dipole forces
(polar molecules)
dispersion forces (LDFs)
(nonpolar, temporary dipoles from e– motion)
(diff electronegativies)
(polar bonds arranged
asymmetrically) H Cl H Cl
Strength
WS KMT (finish), WS IMAFs

13. Special Properties of Water caused by strong attractions:
(hydrogen bonding)
higher bp (liquid)
(100oC instead of –70oC)
surface tension (bead)
density: solid < liquid

14. Quick Quiz!
1. Which of the following IMAF’s is caused by the motion of electrons?
polar bonds
dispersion forces
dipole–dipole forces
hydrogen bonds

15. 2. Which of the following bond types is the strongest bond?
Quick Quiz.
2. Which of the following bond types is the strongest bond?
dipole–dipole forces
dispersion forces
covalent bonds
hydrogen bonds
strongest IMAF!!!

16. Quick Quiz.
3. Molecules have hydrogen bonding when a hydrogen atom is…
attracted to other ions
affected by the motion of electrons
bonded to N, O, or F
attracted to an N, O, or F on another nearby molecule

17. 4. Which of the following is caused by H-bonding in water? low density
Quick Quiz.
4. Which of the following is caused by H-bonding in water?
low density
electrical tension
higher boiling point
dispersion forces
(liquid at room temp)

18. Quick Quiz.
5. Which of the following processes shows the breaking of intermolecular attractions?
A. H2O(s)  H2O(l)
B. Fe2O3(s)  2 Fe(s) O2(g)
C. F2(g)  2 F(g)
D. NH3(l)  3 H2(g) + N2(g)