# When do we use wedges and lines for VSEPR?

It is always difficult to represent a three dimensional object on two dimensional paper. A tetrahedron is a problem, so are trigonal bipyramids and octahedra. Now, when we represent a tetrahedron, say $C {H}_{4}$, we can draw 2 $C - H$ bonds in the PLANE of the page, and a WEDGE to represent the bond that PROJECTS OUT of the page, and a DASHED LINE to represent the bond that PROJECTS INTO the page.