1. Slide 1 of 19 Chemistry 13.3

2. © Copyright Pearson Prentice Hall Slide 2 of 19 The Nature of Solids In 1985, scientists discovered a new form of carbon. They called this form of carbon buckminsterfullerene, or buckyball for short. You will learn how the arrangement of particles in solids determines some general properties of solids. 13.3

3. © Copyright Pearson Prentice Hall The Nature of Solids > Slide 3 of 19 A Model for Solids How are the structure and properties of solids related? 13.3

4. © Copyright Pearson Prentice Hall The Nature of Solids > Slide 4 of 19 A Model for Solids The general properties of solids reflect the orderly arrangement of their particles and the fixed locations of their particles. 13.3

5. © Copyright Pearson Prentice Hall The Nature of Solids Slide 5 of 19 > A Model for Solids The melting point (mp) is the temperature at which a solid changes into a liquid. 13.3

6. © Copyright Pearson Prentice Hall The Nature of Solids > Slide 6 of 19 Crystal Structure and Unit Cells What determines the shape of a crystal? 13.3

7. Slide 7 of 19 © Copyright Pearson Prentice Hall > The Nature of Solids Crystal Structure and Unit Cells In a crystal, the particles are arranged in an orderly, repeating, three-dimensional pattern called a crystal lattice. 13.3

8. © Copyright Pearson Prentice Hall The Nature of Solids > Slide 8 of 19 Crystal Structure and Unit Cells The shape of a crystal reflects the arrangement of the particles within the solid. 13.3

9. Slide 9 of 19 © Copyright Pearson Prentice Hall > The Nature of Solids Crystal Structure and Unit Cells Crystal Systems A crystal has sides, or faces. Crystals are classified into seven crystal systems. 13.3

10. Slide 10 of 19 © Copyright Pearson Prentice Hall > The Nature of Solids Crystal Structure and Unit Cells These minerals show four out of the seven crystal systems. 13.3

11. Slide 11 of 19 © Copyright Pearson Prentice Hall > The Nature of Solids 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 any one of fourteen kinds of unit cells. There are from one to four types of unit cells that can be associated with each crystal system. 13.3

12. Slide 12 of 19 © Copyright Pearson Prentice Hall > The Nature of Solids Crystal Structure and Unit Cells Three kinds of unit cells can make up a cubic crystal system. 13.3

13. Slide 13 of 19 © Copyright Pearson Prentice Hall > The Nature of Solids 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. 13.3

14. Slide 14 of 19 © Copyright Pearson Prentice Hall > The Nature of Solids Crystal Structure and Unit Cells Carbon Allotropes 13.3

15. Slide 15 of 19 © Copyright Pearson Prentice Hall > The Nature of Solids 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. 13.3

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