Question

1. Construct a model consisting of a tetrahedral carbon center with four different component atoms attached: red, white, blue, green; each color represents a different group or atom attached to carbon. Does this model have a plane of symmetry (1a)? A plane of symmetry can be described as a cutting plane-a plane that when passed through a model or object divides it into two equivalent halves; the elements on one side of the plane are the exact reflection of the elements on the other side. If you are using a pencil to answer these questions, examine the pencil. Does it have a plane of symmetry (1b)? 2. Molecules without a plane of symmetry are chiral. In the model you constructed in no. 1, the tetrahedral carbon is the stereocenter; the molecule is chiral. A simple test for a stereocenter in a molecule is to look for a stereocenter with four different atoms or groups attached to it; this molecule will have no plane of symmetry. On the Report Sheet (2) are three structures; label the stereocenter in each structure with an asterisk (*). 3. Now take the model you constructed in no. 1 and place it in front of a mirror. Construct the model of the image projected in the mirror. You now have two models. If one is the object, what is the other (3a)? Do

Answer 1

Ans 1(a): No, the tetrahedral cabon with 4 different groups or atoms attached to it will not have a plane of symmetry. It means you will never get 2 equivalent halves no matter where you pass your plane from and at whichever angle.

Ans 1(b): If you are using your pencil then yes, your pencil has a plane of symmetry. It means you will get two equivalent halves if you pass a plane from your pencil vertically.

Ans 3: The model obtained using the mirror reflection/image of the model 1 is known as enantiomer. (Enantiomers are the stereoisomers which are non-superimposable mirror images of each other)