Question

1. Construct a model that has a central carbon atom with four different colored spheres attached to it, representing four different atoms or groups. Fill in the line-and-wedge drawing below to represent this model and answer the following question: (a) Does the model have a plane of symmetry?

The central carbon atom is said to be a chirality center. Most molecules of nature are chiral. The word “chiral” is derived from the Greek word, cheir and means “handed.” Chiral molecules are related to their mirror images in the same way that your left hand is related to your right hand. They are not identical!

Change one of the colored spheres so that two of the four spheres are the same

(b) fill in a 3-D and answer the following questions:

c) Does the molecule now possess a plane of symmetry?

d) In view of your answers to a–b above, what condition is necessary for a molecule to be chiral?

2. Reconstruct the original carbon with four different colored spheres. Set the model on the table. Construct another model that is the mirror image of the first and place it on the table.

a) Try to superimpose the two models. Are they the same or different? If different, in what sense?

b) What is the stereochemical term that relates these two models?

c) What two important properties must the two molecules (models) each have to be related by the term that is the answer to 3b?

Choose one colored sphere on a model and remove it - Change it to match another color on that model. Do the exact same thing on the other model.
d) Are the models still mirror images?

e) Do the models have a plane of symmetry? If there is a plane of symmetry, describe its location.

f) Are the models superimposable?
g) Do the models represent identical or different molecules? Are they chiral? Explain.

Answer 1

1 a)

​There is one simetry plane. It is an axial simmetry. Those images can not been trasposed

1b)

1c) Last image does not have any simmetry plane and can be transposed.

1d) A molecule needs to have a ccentral atom and at least four different substitutes to be chiral. This is because the molecule can not be converted one in the other by simply rotation or translation.

Part 2a) I am going to try to superimpose these two images.

As can we seen in these two images, they can not be superimposed. They are not the same molecule because they differs in bonds distribution.

​2b) The stereochemical term that relates these two models are the terms R or S. If we puts the least priority bond outside the image and the priority of the other bonds rotates clockwise, it is the isomer R. Nonetheless, if rotates opposite of clockwise, it is the S isomer.

2d) The images are still being mirror images.

2e) This model havs any plane of simmetry        

2f) The models are not superimposable

2g) The models represent two different molecules because it can not be converted one molecule in another by rotation or traslation. There are chiral's molecules because there is a central atom with 4 different sustitutes that can not be trasposed.