Chapter 10-11

• what is Lattice energ?

  The energy associated with the formation of a crystalline lattice from gaseous ions
• As q1 and q2 increase lattice energy will?

  Increase
• As the ionic radii increases what happens to the Lattice energy?

  Becomes less endothermic
• What happens to the Lattice energy As magnitude of ionic charge increases?

  Lattice energy becomes more exothermic
• Ionic compounds have a high or low melting point? why?

  High. it takes a lot of energy to pull the ions apart do to coulomb forces.
• Do solid ionic compounds conduct electricity?

  No. Because the ionic solid has no free electrons to conduct electricity.
• How do you determine the compound with the highest melting point?

  It has the smaller radii and the largest charges.
• a single bond is the…?

  weakest and longest bond.
• Endo vs Exothermic.

  Ionization energy= Endothermic

  Forming bonds = Exothermic

  Breaking bonds = Endothermic

  Sublimation = Endothermic

  Lattice Energy = Exothermic
• Types of bonds:

  • Ionic bond: a chemical bond between a non-metal and metal, where electrons are transferred. ioni bonds have a high melting point and boiling point due to columbic forces holding the ions together.
  • Covalent bond: a bond between 2 non-metals where electrons are shared
  • Metallic bond: a bond between 2 metals where electrons are pooled
• Bond types based on electronegativity difference:

  • Small (0-0.4): Covalent
  • Intermediate (0.4-2.0): Polar covalent
  • Large (2.0+): Ionic
• Summarizing Bond Energies:

  • A reaction is exothermic when weak bonds break and strong bonds form
  • A reaction is endothermic when strong bonds break and weak bonds form
  • Breaking bonds always requires energy
  • Forming bonds releases energy
• Main Group Trends in Electronegativity:

  • Electronegativity generally increases across a period in the periodic table to the right
  • Electronegativity generally decreases down a column in the periodic table
  • Fluorine is the most electronegative element
  • Francium is the least electronegative element
• Electronegativity:

  • The relative ability of an atom to attract electrons to itself in a chemical bond
  • The more electronegative an atom is, the more strongly it will attract electrons
• There is an ionic character to some covalent bonds:

  • One atom may have a higher share of the shared electrons
  • This is due to the difference in electronegativity of the elements
• Determine Electronegativity Diference and assign a bond type and give example.

  Small(0-0.4)= Covalent - Cl2

  Intermediate(0.4-2.0) = Polar Covalent - HCl

  Large(2.0+) = Ionic - NaCl

  Large
• What is Electronegativity ?

  The ability of an atom to attract electrons to itself in a chemical bond.