ionic compounds

• What is an ion?

  An ion is an atom or group of atoms with a positive or negative charge.
• How do ions form?

  Ions form when atoms lose or gain electrons to obtain a full outer shell.
• What do metal atoms do to form ions?

  Metal atoms lose electrons to form positively charged ions.
• What do non-metal atoms do to form ions?

  Non-metal atoms gain electrons to form negatively charged ions.
• What happens to metal atoms when they form ions?

  They lose electrons from their outer shell, resulting in positive ions.
• What is the electronic structure of ions formed from metal atoms?

  The ions have the electronic structure of a noble gas with a full outer shell.
• For elements in groups 1, 2, and 3, how many electrons do they lose to form ions?

  The number of electrons lost is the same as the group number.
• How does a sodium atom become a sodium ion?

  A sodium atom loses one electron to form a sodium ion.
• How do non-metal atoms form ions?

  They gain electrons to form negatively charged ions.
• What is the electronic structure of ions formed from non-metal atoms?

  The ions have the electronic structure of a noble gas with a full outer shell.
• For elements in groups 6 and 7, how is the charge on the ion determined?

  The charge on the ion is equal to (8 minus group number).
• What is the charge on sulfur ions, and is it positive or negative?

  The charge is negative, since sulfur is a non-metal, and the charge is (8 - 6) = 2.
• What is an ionic compound?

  An ionic compound is a giant structure of ions.
• What is an ionic lattice?

  An ionic lattice is a regular, repeating arrangement of ions.
• Why do ionic compounds form crystals with regular shapes?

  Because the lattice arrangement continues in three dimensions.
• What holds an ionic lattice together?

  Strong electrostatic forces of attraction between oppositely charged ions.
• What is ionic bonding?

  Ionic bonding is the attraction between oppositely charged ions.
• What are the advantages and limitations of different models used to represent giant ionic structures?

  Advantages:

  • Two-dimensional space-filling model shows arrangement in one layer.
  • Three-dimensional ball and stick model shows larger sections of the crystal.

  
  

  Limitations:

  • Two-dimensional model does not show next layer arrangement.
  • Ball and stick model misrepresents bond directions and free space.
• How do positive and negative ions form ionic bonds?

  They form when a metal reacts with a non-metal by transferring electrons.
• What do dot and cross diagrams represent?

  They model the transfer of electrons from metal atoms to non-metal atoms.
• What happens when sodium reacts with chlorine?

  Electrons transfer from sodium atoms to chlorine atoms.
• What are the properties of ionic compounds?

  • Regular structures called giant ionic lattices.
  • High melting and boiling points.
  • Conduct electricity when melted or in solution.
  • Insulators when solid.
• Why do ionic compounds have high melting and boiling points?

  Because strong electrostatic forces of attraction must be overcome.
• What must happen for a substance to melt or boil?

  Energy must be transferred to overcome the strong electrostatic forces of attraction.
• How does the strength of ionic bonds relate to the charge on the ions?

  Ionic bonds are stronger for ions with higher charges.
• What is the melting point of NaCl?

  801°C
• What is the boiling point of MgO?

  3,600°C
• What conditions allow ionic compounds to conduct electricity?

  When they are melted or dissolved in water to form an aqueous solution.
• Why can't ionic compounds conduct electricity in the solid state?

  Because their ions are held in fixed positions and cannot move.