Types of Chemical Formulas

• Molecular models—three-dimensional representations of molecules—are used to represent compounds.
• We use two types of molecular models: ball-and-stick and space-filling.
• In ball-and-stick models, we represent atoms as balls and chemical bonds as sticks.
• The balls and sticks are connected to represent the molecule’s shape. The balls are color coded, and each element is assigned a color as shown in the margin.
• In space-filing models, atoms fill the space between each other to more closely represent our best idea for how a molecule might appear if we could scale it to a visible size.