Chemists use molecular models for a variety of reasons.
The material presented here purposes to show you how models can make it easier to understand even fairly simple chemical systems. A number of conventions have been developed whose intent is to minimize the ambiguities and loss of information that necessarily accompany any attempt to represent the shape of molecule using a two-dimensional medium. That is, both atoms are equidistant from you, the observer. In the figure above, both the central C atom and the Br atom can be imagined to line in the plane of the paper. If atoms are joined with a solid line that grows fatter at one end, the atom at the fat end of the bond is closer to you.