The three common states of matter are:

Definite volumeDefinite shape

Definite volumeIndefinite shape

Indefinite volumeIndefinite shape

Three basic assumptions:

1. All matter is composed of small particles (atoms, molecules, ions). The amount of space (volume) that the particles take up depends upon the distance between the particles and not on the size of the particles themselves.

2. These particles are in constant random motion.

3. The particles undergo elastic collisions (no loss of energy) with each other and the walls of their container.

Absolute zero: The temperature at which ALL molecular motion stops. (0 K = -273°C = -460°F)

Solids: The particles in solids can be arranged in three different ways.

1. In a regular repeating pattern that extends over long distances.

A glassy material:Short-range order only

A crystalline material:Has long-range order

2. With a pattern that only repeats over short distances.

3. Amorphous solids have no long or short range order.

Charcoal:Amorphous carbon

Graphitic carbon:‘glassy’ carbon

Diamond:Crystalline carbon

Allotropes: different structural forms of the same element

Intermolecular Forces: the properties of materials (solubility, viscosity, boiling point, freezing point, heat capacity*) depend upon the strength of the interactions BETWEEN the particles.

There are six types of intermolecular forces:

1. Ion-ion

2. Ion-dipole

3. H-bonding

4. Dipole-dipole

5. Dipole-induced dipole

6. Induced dipole-induced dipole (also called London Dispersion Forces, or LDF)

STRONGEST

weakest

1. Ion-ion: exists between oppositely charged ions (atoms that have gained or lost electrons and are no longer electrically neutral). The strength of this interaction increases as the magnitude of the charge increases.

<<Na+1 Cl-1 Mg+2 O-2

NaCl is soluble in water, MgO is not.

2. Ion-dipole: exists between ions and polar molecules (e.g. water, alcohols)

3. H-bonding: Is a special case of dipole-dipole interaction because it is significantly stronger. It occurs whenever H is

bonded to either N, O or F.

C F

H

H

H

CH

H

H

OH

C

H

H

H

OH

+

-

No intermolecularH-bonding possible

H-bonding between H on OH and O on next OH

4. Dipole-dipole: interaction between molecules with permanent dipoles that do not have H-bonding

5. Dipole-induced dipole: The permanent dipole of a permanent dipole causes a distortion of the electron cloud around a nonpolar molecule and INDUCES A TEMPORARY DIPOLE.

HCN+ -

C6H14

6. Induced dipole-induced dipole: A temporary redistribution of the electron cloud around a NONPOLAR molecule induces a temporary dipole in an adjacent NONPOLAR molecule.

C6H14C6H14