Final answer:
Models of molecules such as the molecular formula, structural formula, ball-and-stick models, wedge-and-dash representations, and space-filling models show different aspects of a molecule's structure, from the types of atoms present to their three-dimensional arrangement and relative sizes.
Step-by-step explanation:
Models of molecules and extended structures show the arrangement of atoms and the bonds between them within a molecule. The molecular formula, such as CH4O for methanol, indicates the types and numbers of atoms present but not their arrangement. In contrast, the structural formula shows which atoms are connected and in what sequence, though it can sometimes imply molecules are planar when they are not.
For demonstrating the three-dimensional structure, ball-and-stick models are useful, as they represent atoms as spheres (balls) and their bonds as rods (sticks). The wedge-and-dash representation, or perspective drawing, attempts to show the spatial arrangements of atoms using wedges for atoms above the paper plane and dashes for atoms below. The space-filling model demonstrates the relative sizes of atoms in a molecule without explicitly showing the bonds, which can sometimes result in atoms at the front obscuring those at the back.