Module 1 : Atomic Structure
Lecture 1 : Structural Chemistry
 
After looking at the previous structures, two questions are automatic. How are these determined? What is the theoretical basis of understanding these structures? The experimental basis is spectroscopy, which will be discussed in later chapters. We turn to the theoretical basis first. From the theoretical basis which is given by quantum mechanism, all the above structures can be "derived" or understood.
 

Electronic structure

With electronic structure we cannot associate “geometries” such as molecular geometry or geometrical arrangements corresponding to other objects. Electrons are neither point objects nor stationary objects. Associated with a “stable” arrangement of electrons around one or more nuclei are

 
a) a set of discrete energy levels.
   
b) an electronic configuration resulting form the occupation of electrons in these energy levels.
 
c) an electronic charge density which can be measured experimentally.
 
d) an energy spectrum resulting from the transitions between these levels.

 

By electronic structure, we mean all of a), b), c) and d) above and this will be illustrated in the next few chapters.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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