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. It is the same as the freezing point.

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
The shape of a crystal reflects the arrangement of the particles within the solid.

7. Crystal Structure and Unit Cells
13.3
Crystal Structure and Unit Cells
Crystal Systems
A crystal has sides, or faces. Crystals are classified into seven crystal systems.
Crystals are classified into seven crystal systems. Classifying In which of the systems are all three angles equal to 90°?

8. Crystal Structure and Unit Cells
13.3
Crystal Structure and Unit Cells
These minerals show four out of the seven crystal systems.
Crystals are classified into seven crystal systems. Classifying In which of the systems are all three angles equal to 90°?

9. Crystal Structure and Unit Cells
13.3
Crystal Structure and Unit Cells
The smallest group of particles within a crystal that retains the geometric shape of the crystal is known as a unit cell.
A crystal lattice is a repeating array of unit cells.

10. Crystal Structure and Unit Cells
13.3
Crystal Structure and Unit Cells
Three kinds of unit cells can make up a cubic crystal system.
The unit cell in a cubic crystal system may be simple cubic, body-centered cubic, or face-centered cubic. In the space-filling models and line drawings, the spheres represent atoms or ions.

11. 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.

12. 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?

13. Crystal Structure and Unit Cells
13.3
Crystal Structure and Unit Cells
Non-Crystalline Solids
An amorphous solid lacks an ordered internal structure.
Rubber, plastic, asphalt, and glass are amorphous solids.
A glass is a transparent fusion product of inorganic substances that have cooled to a rigid state without crystallizing.

14. 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.

15. 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)

16. 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.

17. END OF SHOW