Answer:
The models are larger versions of atoms/molecules. It is a visualization so we can understand the super small particles.
Explanation:
Atoms and molecules are very, very, small. They average 100 picometers across.
They definitely cannot be seen with the naked human eye. We can only see them with special microscopes (electron, optical, etc). that magnify hundreds of thousands of times.
So, we use models of atoms and molecules. It allows us to study, visualize, understand, and "see" the particles on a much larger scale.