5 - Ionic And Covalent Bonding

Question 1

Melting and boiling point can increase

Answer 1

• depending on bonding
• If it has a high charge on the ionic bonding
• it’s structure

Question 2

How are ionic molecules soluble

Answer 2

• polar water molecules are attracted to the ions on the surface of the ionic lattice
• water molecules bond to the ions (oppositely charged), weakening the ionic bonding
• ionic bonds are broken
• ions become surrounded by water molecules and break from the lattice

Question 3

But..what does solubility depend on

Answer 3

• in compounds with large charges, the ionic attraction in lattice is too strong to be broken and so will not be soluble

E.g NaCl compared to CaCO3

Question 4

Remember.. solubility

Answer 4

-needs two steps : ionic lattice being broken and water molecules attracting and surrounding ion
- so: solubility therefore depends on relative strengths of attractive forces in the lattice and between water mol and ions.
USUALLY - solubility decreases as ionic charge increases