Ionic Compounds

• What is an ion?

  An atom or group of atoms with charge
• How do ions form?

  Atoms lose or gain electrons for stability
• What do metal atoms do to form ions?

  Lose electrons
• What charge do metal ions have?

  Positive charge
• Why are metal ions positively charged?

  They have more protons than electrons
• What electronic structure do metal ions have?

  Structure of a noble gas with full shell
• How many electrons do elements in groups 1, 2, and 3 lose?

  Same as their group number
• What do non-metal atoms do to form ions?

  Gain electrons
• What charge do non-metal ions have?

  Negative charge
• Why are non-metal ions negatively charged?

  They have more electrons than protons
• What electronic structure do non-metal ions have?

  Structure of a noble gas with full shell
• For elements in groups 6 and 7, how is the charge on the ion calculated?

  8 minus the group number
• What are the key differences between metal and non-metal ions?

  • Metal ions:
  • Lose electrons
  • Positively charged
  • Have electronic structure of noble gas
  • Non-metal ions:
  • Gain electrons
  • Negatively charged
  • Have electronic structure of noble gas
• What type of bond is formed between oppositely charged ions?

  Ionic bonds
• What does a dot and cross diagram represent?

  The transfer of electrons between atoms
• In a dot and cross diagram, how are electrons from different atoms represented?

  Dots for one atom, crosses for another
• What happens when sodium reacts with chlorine?

  Electrons transfer from sodium to chlorine
• What is an ionic compound?

  • A giant structure of ions
  • Formed by the attraction of oppositely charged ions
  • Has a regular, repeating arrangement called an ionic lattice
• What is the arrangement of ions in an ionic lattice?

  Regular, repeating pattern
• Why do ions form a regular pattern in an ionic lattice?

  Because they attract each other
• How does the attraction between ions contribute to the structure of an ionic compound?

  It forms a stable, repeating ionic lattice
• What is the typical number of ions in a grain of salt?

  1.2 × 10$^{18}$ ions
• Why do solid ionic compounds form crystals with regular shapes?

  Due to the three-dimensional lattice arrangement
• What holds an ionic lattice together?

  Strong electrostatic forces of attraction
• What is ionic bonding?

  Attraction between oppositely charged ions
• How do the forces in an ionic lattice act?

  In all directions within the lattice
• What are the different models used to represent giant ionic structures?

  • Two-dimensional space-filling model
  • Shows arrangement in one layer
  • Does not show next layer arrangement
  • Three-dimensional ball and stick model
  • Shows larger section arrangement
  • Misleading bond representation
  • Three-dimensional model
  • Misleading due to apparent free space
• What is a limitation of the two-dimensional space-filling model?

  It does not show next layer arrangement
• What is a limitation of the three-dimensional ball and stick model?

  It misrepresents the direction of forces
• What is a limitation of the three-dimensional model of ionic compounds?

  It shows lots of free space between ions
• What must be transferred to a substance to make it melt or boil?

  Energy
• What do the electrostatic forces of attraction act between in ionic compounds?

  Oppositely charged ions
• What happens to some forces during melting?

  They are overcome
• What happens to all remaining forces during boiling?

  They are overcome
• How does the amount of energy needed relate to melting and boiling points?

  The more energy needed, the higher the points
• What are ionic compounds held together by?

  Electrostatic forces
• What is the term used for the forces between oppositely charged ions?

  Ionic bonding
• Why do ionic compounds have high melting and boiling points?

  A lot of energy is needed to overcome ionic bonding
• What does the strength of ionic bonds depend on?

  The charge on the ions
• What happens to ions with higher charge in terms of ionic bonds?

  They have stronger forces between them