Ionic compounds

• What is the structure of ionic compounds called?

  Giant ionic lattice
• How do ions arrange themselves in an ionic compound?


  They form a closely packed regular lattice arrangement.
• What type of forces hold the ions together in an ionic lattice?


  Strong electrostatic forces of attraction between oppositely charged ions.
• What is a single crystal of sodium chloride an example of?


  A giant ionic lattice.
• What are the general properties of ionic compounds?


  • High melting points and boiling points due to strong bonds.
  • Do not conduct electricity when solid.
  • Conduct electricity when melted or dissolved in water.
• Why do ionic compounds have high melting and boiling points?


  Because of the many strong bonds between the ions.
• Why do solid ionic compounds not conduct electricity?


  Because the ions are held in place and cannot move.
• What happens to ionic compounds when they melt?


  The ions become free to move and can carry electric charge.
• What occurs when some ionic compounds dissolve in water?


  The ions separate and are free to move, allowing them to carry electric charge.
• What is the first step in finding the empirical formula of an ionic compound from a diagram?


  Count how many atoms there are of each element.
• What should you do if given a 3D diagram of an ionic lattice?


  Use it to work out what ions are in the ionic compound.
• How do you balance the charges of ions in an ionic compound?


  Ensure the overall charge on the compound is zero.
• What is the empirical formula of a compound containing potassium and oxide ions?


  K₂O
• What charge does a potassium ion form?


  1+ charge
• What charge does an oxide ion form?


  1. charge
• How many potassium ions are needed to balance the charge of one oxide ion?


  Two potassium ions are needed.
• What is the process to determine the empirical formula from a dot and cross diagram?


  1. Count the number of atoms of each element.
  2. Write down the empirical formula based on the counts.
  3. Balance the charges to ensure the overall charge is zero.
• What are ionic compounds made of?


  Positive and negative ions
• How do ions in ionic compounds interact with each other?


  They alternate and attract each other in all directions
• What structure do ionic compounds form?


  Regular lattice structure
• How can ionic compounds be represented visually?


  With ball and stick diagrams
• What are the properties of ionic compounds?


  • High melting and boiling points
  • Conduct electricity when melted or dissolved in water
  • Fixed structure in solid form
  • Ions are free to move when melted or dissolved
• What is the formula for sodium chloride?


  NaCl
• What is the hydroxide ion formula?


  OH⁻
• What is the formula for the sulfate ion?


  SO₄²⁻
• What is the formula for magnesium chloride?


  MgCl₂
• What is the formula for aluminum sulfate?


  Al₂(SO₄)₃
• What is the charge of the aluminum ion?


  [Al]³⁺
• What is the formula for calcium hydroxide?


  Ca(OH)₂
• What is the formula for the nitrate ion?


  NO₃⁻
• What is the formula for the carbonate ion?


  CO₃²⁻
• What is the formula for the ammonium ion?


  NH₄⁺