1. Types of Bonding
Intramolecular
Intermolecular

2. Definitions
 Bond: a type of interaction between atoms
that result in atoms staying close together
 Molecule: two or more atoms held together
by a covalent bond
 Intramolecular: forces of attraction within a
molecule (e.g. intramurals)
 Intermolecular: forces of attraction between
molecules in a compound (e.g. international)

3. Types of Interactions Summary
Intermolecul Intramolecul
ar ar

4. Intramolecular Bonds
 Electronegativity: attraction of an atom for
electrons
 Example of a very electronegative atom:
oxygen
 When two atoms with different
electronegativity get together…

5. Intramolecular Bonds

6. Intramolecular: Ionic
 If two atoms with very large differences in
electronegativity get together, one of atom
could take away an electron from the other
 Acceptor “stealer” of electron becomes
negativity charged (anion = negative ion)
 Donor of electron becomes positively
charged (cation = positive ion)

7. Intramolecular: Ionic
 Ionic bond forms from an attraction between
an anion and cation
 Ionic compounds are formed by ionic bonds
 Salts are ionic compounds (e.g. Na+ + Cl- 
NaCl)
 Salt crystals have a 3D lattice because of +/-
attractions

9. Types of Interactions Summary
Intermolecul Intramolecul
ar ar
Covalent Ionic

10. Intramolecular: Covalent
 Covalent bond forms when atoms share electrons
 Nonpolar covalent bond
 atoms have the same electronegativity
 electrons are equally shared
 e.g. H2
 Polar covalent bond
 atoms have slight differences in electronegativity
 electrons are unequally shared
 e.g. HCl

11. Polar Covalent Bond

12. Polarity of a Molecule
Polarity dependent on the polarity of the bond AND
the molecular SHAPE
Bond
Shape Nonpolar bond Polar bond
nonpolar nonpolar
Symmetrical molecule molecule
(e.g. H2) (e.g. CO2)
nonpolar polar molecule
Assymetrical
molecule (e.g. HCl, H2O)

13. Polar Covalent Bond

14. Polarity

15. Ionic Versus Molecular

16. Types of Interactions Summary
Intermolecul Intramolecul
ar ar
Covalent Ionic
Nonpolar Polar
Covalent Covalent

17. Intermolecular Forces

18. Types of Interactions Summary
Intermolecul Intramolecul
ar ar
London Dipole- Hydrogen Covalent Ionic
(dispersion) dipole bonding &
forces Ion-dipole
Nonpolar Polar
Covalent Covalent

19. London Dispersion
 Exists
between all
molecules
 Weak force,
due to
instantaneous
diploes

20. Dipole-Dipole
 Exists between
polar molecules
 Due to permanent
dipoles

21. Hydrogen Bonding
 Strong force (just a very strong dipole-dipole)
 Between a polar molecule with an H-atom and a
polar molecule with an electronegative atom
(usually O, N or F)

22. Ion-Dipole
Ion-Dipole
 Dipole is attracted to an oppositely charged ion
 When ionic compounds dissolve in water, water
molecules surround the ion and remove it from the
crystal lattice structure (hydration shell)

23. Hydrophobic Interactions
 Nonpolar molecules are
excluded from mixing with polar
molecules
 Nonpolar molecules tend to
associate with each other
 Can occur spontaneously (e.g.
oil molecules spontaneously
associate excluding water)