Let us begin our study of chemisty with a simple question:
Chemistry is about structure: Specifically, it is the study of
the stable structures or chemical bonding patterns
that can be formed by bringing atoms into specific spatial arrangements.
The term ``structure'' can also refer to the beautiful supramolecular
structures that are possible when molecules are brought together into large
assemblies.
Chemistry is also about transformation. Specifically, it is the study of the
transformations of substances into other substances caused by the
interactions of atoms and molecules to form new molecules by
the forming, breaking and reforming of chemical bonds.
What exactly is meant by a chemical bond will be defined more precisely
later in the course and next semester.
While the above definition encompasses much of chemistry, it falls short of
conveying the full breadth of the subject. Chemistry is also the study and
prediction of the properties of substances and the rationalization
of these properties from the microscopic detailed motions of individual constituent
atoms/molecules that result from the forces between them.
Note that both of these aspects refer to a connection between
microscopic dynamics and macroscopic observable phenomena.