5.2 - Ionic Bonding & Structure

Question 1

What is ionic bonding?

Answer 1

Electrostatic force of attraction between +ve and -ve ions.

Holds together cations & anions

Question 2

What is the structure of an ionic compound?

Answer 2

• Each ion attracts oppostiely charged ions in all directions
  
  • results in billions of ions in a giant ionic lattice
    
    • 3D structure of +ve and -ve ions bonded by strong ionic bonds

Question 3

What are the properties of ionic compounds?

Melting & Boiling Point

Answer 3

• High melting/boiling points
• All ionic compounds solid at room temperature
  
  • insufficient energy to overcome bonds
• Large amount of energy required to overcome electrostatic bonds
• Melting points higher for lattices with greater ionic charges
  
  • due to stronger bonds

Question 4

What are the properties of ionic compounds?

Solubility

Answer 4

• Ionic compounds dissolve in polar compounds (e.g. water)
• Polar molecules break down the lattice surrounding individual lattices
• Larger ionic charge → less likely polar solvents will dissolve them (due to charge size)

Solubilitiy depends on strength of attraction between ions & attractions between ions and polar substances

Question 5

What are the properties of ionic compounds?

Electrical conductivity

Answer 5

In the solid state - ionic compounds don’t conduct electricity

• Ions are in fixed position
• No mobile charge carrier (non-conductor)

In liquid state - ionic compounds conduct electricity

• Ionic lattice breaks down
• Ions are mobile and carry charges (conductors)