What determines the physical properties of solids?
The arrangement of atoms and ions in a crystal helps to determine the physical properties of thermal and electrical conductivity, melting and boiling points, physical state at room temperature and solubility in solvents. Solids can be divided into the following groups: ionic crystals, molecular (simple and giant) and metallic crystals. The differences in the properties can be explained by the type of bonds they possess. Ionic compounds are crystalline solids, able to conduct electricity when molten, due to the movement of ions which can carry an electric current. These compounds also have high melting and boiling temperatures, due to the strength of the attractive forces between the ions. Simple molecular crystals have low melting and boiling temperatures, due to weak forces of attraction between molecules. Giant structures of atoms and molecules have very high melting and boiling points, due to strong covalent bonds throughout their three-dimensional network. Metals are able to conduc
