Compounds and Molecules

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Compounds and Molecules

• Chapter 22 - notes

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I. What are compounds?

• A. Compound substance made of atoms of more
  than one element bound together
• 1. Properties of the compound are different from
  those of the component elements

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I. What are compounds?

• 2. Examples ? sodium chloride
• NaCl
• ? made from an alkali metal (soft and shiny), and
  a halogen (poisonous green gas)

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I. What are compounds?

• B. Chemical bond the attractive force that
  holds atoms or ions together
• ? several types some stronger than others

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I. What are compounds?

• C. A compound always has the same chemical
  formula
• Chemical formula shows the types of elements,
  and number of atoms of each element in the
  compound.
• 2. Compounds always have the same elements in the
  same proportions

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I. What are compounds?

• 3. Examples
• Water ? H2O
• 1 oxygen atom
• 2 hydrogen atoms
• Hydrogen Peroxide ? H2O2 2 hydrogen atoms
• 2 oxygen atoms

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I. What are compounds?

• D. Chemical structure shows the bonding within a
  compound
• 1. Chemical structure arrangement of bonded
  atoms or ions in a substance
• ? determines many properties
• 2. Bonds between any 2 atoms are always straight

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II. Models of compounds

• ? helps you see a structure
• A. Ball and stick model
• 1. The ball represents the atom
• 2. The stick represents the bond between two
  atoms

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Ball and Stick Model examples
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II. Models of compounds

• B. Structural formula a drawing representing
  the structure
• 1. Chemical symbols represent atoms
• 2. Lines represent bonds

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Structural Formula Models
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II. Models of compounds

• C. Space filling model
• Shows the actual space occupied by the atoms
• 2. Examples

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Space Filling Model Examples
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III. How does structure affect properties?

• A. Compounds with network structures are strong
  solids
• 1. Networks can be made of atoms or ions
• 2. Network structures have strong bonds
• 3. Strong bonds high melting point

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Network Structures Examples

• 2. Examples

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III. How does structure affect properties?

• B. Compounds can be made of molecules
• 1. Molecule smallest unit of a substance,
  formed of one or more atoms bound together
• ? can be multiple atoms of the same element
  bound together
• ? oxygen we breathe is O2

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III. How does structure affect properties?

• 2. Attractions between two molecules is lower
  than the attractions of the atoms in
• each molecule
• 3. Example C12H22O11
• ? table sugar the atoms are bound together more
  strongly than any two molecules would be to each
  other