I. Introduction to Bonding (p. 161 163) by gregoria

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									Ch. 6 & 7 - Chemical Bonding



     I. Introduction to
           Bonding
         (p. 161 – 163)

                      I   II   III   IV
A. Vocabulary

Chemical Bond
 attractive force between atoms or ions
  that binds them together as a unit
 bonds form in order to…
  decrease potential energy (PE)
  increase stability
A. Vocabulary

   CHEMICAL FORMULA

  IONIC           COVALENT


  Formula       Molecular
    Unit        Formula


  NaCl           CO2
A. Vocabulary

          COMPOUND
                 more than 2
 2 elements
                  elements

   Binary        Ternary
 Compound       Compound


  NaCl          NaNO3
A. Vocabulary

            ION
   1 atom         2 or more atoms


Monatomic         Polyatomic
   Ion                Ion


  Na+              NO3-
  B. Types of Bonds
                       IONIC                 COVALENT
Bond            e- are transferred from   e- are shared between
Formation          metal to nonmetal          two nonmetals
Type of
                    crystal lattice          true molecules
Structure
Physical
State                    solid                liquid or gas
Melting
                         high                     low
Point
Solubility in
                          yes                  usually not
Water
Electrical                yes
Conductivity      (solution or liquid)             no
Other
Properties                                      odorous
B. Types of Bonds
                      METALLIC
    Bond             e- are delocalized
    Formation       among metal atoms
    Type of
                      “electron sea”
    Structure
    Physical
                          solid
    State
    Melting              very high
    Point
    Solubility in           no
    Water
    Electrical             yes
    Conductivity        (any form)
    Other           malleable, ductile,
    Properties           lustrous
C. Bond Polarity

Most bonds are
 a blend of ionic
 and covalent
 characteristics.
Difference in
 electronegativity
 determines bond
 type.
C. Bond Polarity

Electronegativity
 Attraction an atom has for a shared pair
  of electrons.
 higher e-neg atom  -
 lower e-neg atom +
C. Bond Polarity

Electronegativity Trend (p. 151)
 Increases up and to the right.
C. Bond Polarity

Nonpolar Covalent Bond
 e- are shared equally
 symmetrical e- density
 usually identical atoms
C. Bond Polarity

Polar Covalent Bond
 e- are shared unequally
 asymmetrical e- density
 results in partial charges (dipole)




 +                                 -
  C. Bond Polarity


Nonpolar


Polar


Ionic

 View Bonding Animations.
C. Bond Polarity

              Examples:
              Cl2    3.0-3.0=0.0
                      Nonpolar

              HCl    3.0-2.1=0.9
                      Polar

              NaCl   3.0-0.9=2.1
                      Ionic

								
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