Chapter 8

• Bond energy is the energy required to break 1 mole of a given bond.
• Bond length is the distance between the nuclei of two atoms that are chemically bonded.
• Cations are smaller than their atoms and anions are larger than their atoms.
• Lattice energy is the energy released when 1 mole of a crystalline ionic solid is formed from its gaseous ions under standard conditions.
• The greater the charges on the ions, the more negative is the LE.
• The smaller the ions the more negative is the LE.
• How does lattice energy become more negative?

  Greater charges on ions
• Atomization energy is the energy needed to make 1 mole of gaseous atoms from their naturally occurring elements under standard conditions.
• For diatomic elements, bond dissociation energy is twice the atomization energy.
• Formal Charge = # of valence es in the free atom – # of lone es – (half the # of bonded es)
• What is the formal charge?

  # of valence es in the free atom – # of lone es – (half the # of bonded es)
• The resonating structure with the smallest formal charges is the most probable Lewis structure.