Final answer:
Ionic substances dissolve in polar compounds due to the attraction between the polar solvent molecules and the ions, while their brittleness is caused by the crystal lattice structure.
Step-by-step explanation:
Visual Representation of Ionic Substances
To connect the microscopic structure of ionic substances to their macroscopic properties, we can consider the following:
- Solubility in polar compounds: Ionic substances dissolve in polar compounds due to the attraction between the polar solvent molecules and the ions. The ionic bonds between the ions in the crystal lattice of the substance are broken, allowing the ions to separate and disperse throughout the solvent.
- Brittleness: Ionic substances are brittle because their crystal lattice structure consists of alternating positive and negative ions held in fixed positions by strong electrostatic attractions. When an external force is applied, the ions are forced out of their positions, causing the crystal lattice to fracture along planes.
Overall, ionic substances possess these properties due to their strong ionic bonding and rigid crystal lattice structure.