Forming Chemical Bonds
             • According to the Lewis model
                 – an atom may lose or gain enough electrons to 
                   acquire a filled valence shell and become an ion. 
                   An ionic bond is the result of the force of 
                   attraction between a cation and an anion.
                 – an atom may share electrons with one or more 
                   other atoms to acquire a filled valence shell. A 
                   covalent bond is the result of the force of 
                   attraction between two atoms that share one or 
                   more pairs of electrons.
                                                Material from karentimberlake.com 
                                                and 
                                                H. Stephen Stoker
  Ionic Compounds 
     Vs
     Covalent
    (Molecules) 
    Compounds
 •Ionic Compounds
  –Made up of a metal and a non-metal
  –Have a difference in electronegativity of more than 
  1.7 (Figure 20 pg. 161)
  –Formed from ions
  –Electrons are transferred
 • Covalent Molecules
  –Made up of two non-metals
  –Have a difference in electronegativity of 
  less than 1.7 (Figure 20 pg. 161)
  –Ions are not formed
  –Electrons are shared
                        Bond Polarity: Nonpolar
          Nonpolar covalent bond  
          Electrons are shared between atoms with the same 
              electronegativity values.
          Difference = 0
          Examples:    
              N2         Br2