Bonding
   • Bond Energy – Energy required to break a chemical 
    bond
   • Atoms bond in a way that achieves the lowest possible 
    energy for the system
   • Bond length – distance between the nuclei of two 
    bonded atoms 
    –Shorter bond length = stronger bond = higher bond 
     energy!!
          Ionic Bonding
  • Electrons are transferred 
  • Metals react with nonmetals
  • Ions paired together have lower energy (greater stability) 
   than separated ions
  • Ionic compounds conduct electricity in a molten state
        Coulomb’s Law
  • Shows energy of interaction between a pair of 
   ions
  • E = Energy, r = distance between ionic nuclei, 
   Q = ionic charge
  • Lower energy = stronger attraction, more 
   favorable interaction
        Covalent Bonding
  • Electrons are shared by nuclei
   – Pure covalent (non-polar covalent)
     •  Electrons are shared evenly
   – Polar covalent bonds
     • Electrons are shared unequally
     • Atoms end up with fractional charges
     • d+ or d- (partial charges)
        Electronegativity
  • The ability of an atom in a molecule to attract 
   shared electrons to itself.
  General Trend – Increases to the right, Increases going up 
  on the Periodic Table