Organic compounds are made up of carbon, oxygen,  hydrogen, and few other elements. However, the number of organic compounds is far bigger than inorganic compounds that do not form bonds.

The distinct nature of carbon atom and its capacity to form bonds with other atoms leads to such huge number of organic compounds.

The versatile nature of carbon can be best understood with its features such as, tetravalency and catenation. In this section let us learn more about versatility of carbon.

Carbon is a versatile element and is found in many different chemical compounds, including those found in space. Carbon is versatile because it can form single, double, and triple bonds. It can also form chains, branched chains, and rings when connected to other carbon atoms.

The two characteristic features seen in carbon, that is, tetravalency and catenation, put together give rise to a large number of compounds. Many have the same non-carbon atom or group of atoms attached to different carbon chains.

Catenation: The property of forming long chains by self-linking with other carbon atoms to form long chains, rings, double or triple bonds is called catenation.

Isomerism: Compounds with same molecular formula but different structural formula are called isomers. An isomerism commonly seen is due to difference in the arrangement of atoms or groups of atoms & is called structural isomerism. The 4 types of structural isomerism are: Chain isomerism, Position, Functional and Metamerism.

Tetravalency:- Carbon has 4 electrons in its valence shell. Energy considerations do not allow it to gain or lose 4 electrons; therefore it forms covalent bonds with other elements to complete its octet. This accounts for its tetravalency and explains its ability to form a variety of compounds.

Hydrocarbons:-
These are organic compounds containing only carbon and hydrogen and are represented by the general formula C x H y  where x and y are whole numbers. Other organic compounds are derived from these parent compounds by replacement of one or more hydrogen atoms, e.g. the addition of one -CH₂ group can result in the formation of a new compound.

Homologous series of compound is a family of carbon compounds which:

* Have the same general formula.
* Show a difference of 14 u in their molecular mass.
* Show gradation in the physical properties.
* Show similarity in the chemical properties.
* Are characterised by the same functional group.
* Differ from the previous member by a –CH₂ group.

Example, CH3-OH, CH3-CH2-OH etc..,

Rules to ne Carbon compounds:-

Choose the longest unbranched carbon chain.Determine the functional group present.Number the carbon atoms such that the C atom to which the functional group is present gets the smallest number.If the same substituent occurs more than once, the location of each point on which the substituent occurs is given & the number of times the substituent group is indicated by a prefix (di, tri, tetra etc.).

The unique nature of carbon atom and the arrangement of the bond carbon forms with other atoms enable the existence of a large number of organic compounds. It can form so many compounds due its tetravalent nature and catenation property.