There are two basic types of compounds. They are distinguished by by the manner in which the atoms bind to one another in the compound. These two types are called "molecular" compounds and "salts" (or equivalently "ionic" compounds):

Molecular compounds: These compounds are made up of molecules whose atoms bind to one another through "covalent" bonds.
Salts: The atoms in salts are held together with "ionic" bonds. Unlike molecules, salts always form solids in a regular array called a "crystalline solid".

A bond is the "glue" that holds atoms together. In compounds this glue can either be covalent or ionic.

Covalent bonds: The electrons are shared between atoms. Therefore this sharing of electrons provides the glue.
Ionic bonds: Ionic bonds occur due to the mutual attraction between atoms with positive and negative charges i.e., ions.

Examples of Molecules







An Example of a Salt


Sodium Chloride (NaCl)

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C101 Class Notes
Prof. N. De Leon