SQA Higher Chemistry Practice Exam

Ionic compounds typically form crystalline lattice structures of oppositely charged ions due to the strong electrostatic forces of attraction between the positively charged cations and negatively charged anions. In a crystalline lattice, these ions are arranged in a repeating pattern that maximizes the attraction between oppositely charged ions while minimizing the repulsion between like charges. This orderly arrangement contributes to the characteristic properties of ionic compounds, such as high melting and boiling points, as well as their hardness and brittleness.

The lattice structure is a defining feature of ionic compounds, as it contrasts with molecular compounds, which are composed of individual discrete molecules and do not form such organized structures. Likewise, the term 'amorphous' is used to describe solids that lack a defined crystalline structure, and 'chains of molecular structures' is not applicable to ionic compounds, as they do not consist of covalently bonded molecular chains but rather extend into a three-dimensional network.