Notes
Slide Show
Outline
1
Chemical Bonding
  • Compounds are formed from chemically bound atoms or ions.
  • Bonding involves only the valence electrons.
2
Chemical Bonding
  • Ionic Compounds
    • Ionic Radii
    • Lattice Energy
  • Molecular Compounds
    • Covalent bonds
    • Bond Order
    • Bond Strength
    • Lewis Structures
3
Lewis Symbols
  • Lewis symbols show the valence electrons as dots arranged around the atomic symbol.
  • hydrogen:
  •    sodium:
  •   chlorine:
4
The Octet Rule
  • Atoms tend to gain, lose, or share electrons until they have eight valence electrons.
5
Ionic and Molecular Compounds
  • Formation of sodium chloride:
6
Ionic Compounds
  • Ionic compounds consist of a lattice of positive and negative ions.
7
Ionic Bonds
  • An ionic bond is simply the electrostatic attraction between opposite charges.
8
Ionic Sizes
9
The Lattice Energy
  • The lattice energy is the enthalpy change required to separate one mole of an ionic compound into its ions:
  •       NaCl(s) ® Na+(g) + Cl-(g)      DH = 788 kJ
  • Lattice energy increases with increasing  ionic charges and decreasing ionic sizes.
  •       KCl(s) ® K+(g) + Cl-(g)           DH = 701 kJ
  •   MgCl2(s) ® Mg+2(g) + 2 Cl-(g)    DH = 3795 kJ