1. Molecules and Crystal Structures
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What are molecules?
How are crystals formed?
Classifying Matter
I will be able to:
Identify the atom as the basic unit of matter and describe its structure.
Differentiate between elements, compounds, and molecules.
Identify examples of elements or molecules by using chemical symbols or models.

2. Compounds & Molecules
Molecule: The smallest identifiable unit that retains the physical and chemical properties of the pure substances.
NaCl, salt
Ethanol, C2H6O
To play the movies and simulations included, view the presentation in Slide Show Mode.
Buckyball, C60

3. Compounds & Molecules
COMPOUND is a combination of 2 or more elements in definite ratios by mass.
The character of each element is lost when forming a compound (e.g., think of NaCl).
MOLECULES are the smallest units of a compound that retains the characteristics of the compound.

4. MOLECULAR FORMULAS Formula for glycine is C2H5NO2
(description of the composition)
In one molecule there are
2 C atoms
5 H atoms
1 N atom
2 O atoms

5. Formula for glycine is NH2CH2CO2H In one molecule there are
CONDENSED FORMULAS
Formula for glycine is NH2CH2CO2H
In one molecule there are
1 NH2 (amine group)
1 CH2 group
1 CO2H group

6. Show how the atoms are attached within a molecule.
STRUCTURAL FORMULAS
Show how the atoms are attached within a molecule.
The lines between atoms represent chemical bonds that hold the atoms together.
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7. MOLECULAR MODELING Drawing of glycine Ball & stick Space-filling
An even higher level of structural detail
Drawing of glycine
Ball & stick
Space-filling

8. Naming Molecular Compounds
All are formed from two or more nonmetals.
CO2 Carbon dioxide
Ionic compounds generally involve a metal and nonmetal
(NaCl)
BCl3 boron trichloride
CH4 methane

9. Crystals Most minerals are composed of crystals.
Crystals come in 6 different shapes.
Some can be seen with your eye or magnifier, but others can only be viewed with special X-Ray equipment.

10. Crystals Form in One of 6 Shapes
Cubic/Isometric, Tetragonal, Hexagonal, Monoclinic, Triclinic, Orthorhombic
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11. Examples

12. Salt Crystals
Salt crystals are referred to as a cubic crystal because they are a pattern of cubes.
The shape of a crystal is the repeating pattern of the particles that make it up. The salt crystals only have one pattern of crystals and they are cubic. Each mineral can contain only one crystal shape. The crystal shape of a mineral will be the same no mater where on earth you find that mineral. Salt crystals are cubic no matter where you find them.

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