2 Replies Latest reply: Mar 24, 2013 8:31 AM by Mitsuru Yamada RSS

Chemical Ball and Spoke Model.  How do you explain when a rearrangement of the model is needed?

Mitsuru Yamada

Chemistry teachers seem to use the ball and spoke model for describing a molecule of a chemical compound in order to teach the youngs its realistic comformation.

I think the model is too simplistic and rigid for young student who is pondering about its possible chemical transformation.

What does each spoke tell about its bond's meaning?

And when a chemical reaction occurs on the compound, then how does a teacher explain the general mechanism that changes the ball and spoke configuration?

This model gives students a fixed idea for chemistry.

Think a wild possibility of electron's behavior now being excavated by quantum mechanics!

 

An old amateur physicist

February 21, 2013


  • Re: Chemical Ball and Spoke Model.  How do you explain when a rearrangement of the model is needed?
    Marcelo Preite

    The classical ball and spoke models are cheap, simple to use, buy just not good enough to show a dynamic process involving formation and destruction of chemical bonds. However, those models are excellent for conformational analysis. Also, they tend to exagerate the relation between bond lengths and atomis sizes: it is a good idea to also use Van der Waals models, at least for some representative molecules.

    In order to understand a reaction process, it is better, IMHO, to use CG animated graphics, and to switch between several types of models during the classes.

    • Re: Chemical Ball and Spoke Model.  How do you explain when a rearrangement of the model is needed?
      Mitsuru Yamada

      Do we know really the true figure of an atom, or of a molecule?

      If there are molecular rotatations or molecular viblations, the ball and spoke model says nothing about them.

      Further, the modern physics teachs us that the electrons are spreading around the nuclei vaguely.

      And futhermore, the nuclei are suffering from thermal agitations.

      The ball and spoke model is weak in these points as an educationl tool.

       

      And the most interesting thing that the students must feel attraction may be the intra molecular mechanism when the molecule reacts with another molecule.  At the time the reaction occurs, there may be rearrangement and transfer of nuclei and electrons within and between the reactants.  But why do they rearrange in such away?  The young students must come to inquire the reason why?  They must want to know the key to resolve the riddle of chemical transformation of the molecules that participated that reaction.

       

      How should we teach youngs the above various facets?