Kekulé Postulates

German chemist Friedrich August Kekulé studied the main features of the carbon atom. He explained the properties in the form of three postulates:

Since the carbon atom has 4 electrons in its last shell, it has four free valences and can make four covalent bonds, forming molecules. In this way the atom is stable.

The carbon atom has the four free valences. The position of the heteroatom does not differ from the compounds.

Example: chloroform (CH3Cl)

Carbon atoms group together, forming carbon structures, or carbon chains.

Some elements (sulfur and phosphorus) can also form chains, just like carbon, but not chains as long, stable and varied as carbon.

General Property of Organic Compounds

Because they have predominant covalent bonding, they are molecules and have the following properties:

- Low P.F.
- Solubility in nonpolar solvents
- Aqueous solution does not conduct electricity
- May have polymeria and isomerism

Types of carbon bonding

Two carbon atoms can bond together through one, two or three bonding pairs.

1 electronic pair - single link C - C
2 electronic pairs - double bond C = C
3 electronic pairs - triple bond C ≡ C