1. 13.3
A Model for Solids
A Model for Solids
How are the structure and properties of solids related?

2. 13.3
A Model for Solids
The general properties of solids reflect the orderly arrangement of their particles and the fixed locations of their particles.

3. 13.3
A Model for Solids
The melting point (mp) is the temperature at which a solid changes into a liquid.

4. Crystal Structure and Unit Cells
13.3
Crystal Structure and Unit Cells
Crystal Structure and Unit Cells
What determines the shape of a crystal?

5. Crystal Structure and Unit Cells
13.3
Crystal Structure and Unit Cells
In a crystal, the particles are arranged in an orderly, repeating, three-dimensional pattern called a crystal lattice.
The orderly arrangement of sodium and chloride ions within a sodium chloride crystal determines the shape of the crystal. The closely packed ions vibrate about fixed points on the crystal.

6. Crystal Structure and Unit Cells
13.3
Crystal Structure and Unit Cells
Allotropes
Allotropes are two or more different molecular forms of the same element in the same physical state.
Allotropes have different properties because their structures are different.
Only a few elements have allotropes.

7. Crystal Structure and Unit Cells
13.3
Crystal Structure and Unit Cells
Carbon Allotropes
Diamond, graphite, and fullerenes are allotropes of carbon. Classifying Based on the arrangements of their atoms, explain why the properties of fullerenes are closer to those of diamond than of graphite?

8. 13.3 Section Quiz.
13.3

9. 13.3 Section Quiz
1. A solid will melt when
all the particles have the same kinetic energy.
bonds form between the particles.
disruptive vibrations overcome attractive forces.
attractions overcome disruptive vibrations.

10. 13.3 Section Quiz (1) only (2) only (3) only (1) and (2)
2. Which of the following affect the shape of crystals?
(1) angles between the faces
(2) number of edges of equal length per face
(3) size of the crystal
(1) only
(2) only
(3) only
(1) and (2)

11. their atoms are arranged in different patterns.
13.3 Section Quiz
3. Allotropes have different properties because
their atoms are arranged in different patterns.
they are composed of different elements.
they are in different states.
they consist of different isotopes of the same element.