Carbon is a nonmetal having symbol C. its atomic no. is 6 and its atomic weight is 12. The electronic configuration of carbon is 2, 4. Valency of carbon is 4 because there are 4 valence electrons present in its outermost energy shell. Carbon is present in group 14 of the periodic table and silicon and germanium are also present in this group.
One of the remarkable properties of carbon atom is that it can combine with other atoms to form a large number of compounds called carbon compounds, and this property of carbon to form carbon compounds is called catenation.
Hydrocarbons
A compound made up of hydrogen and carbon only is called a hydrocarbon. For Example methane (CH4), ethane (C2H6) and propane (C3H8) etc. the simplest hydrocarbon present today is methane (CH4). Hydrocarbons also consist of some more elements such as nitrogen, oxygen, sulphur and halogens in spite of carbon and hydrogen. The most important natural source of hydrocarbons is petroleum (crude oil), which is obtained from underground oil wells by drilling oil wells.
Types of Hydrocarbons
Hydrocarbons are of two types:
1. Saturated hydrocarbons
2. Unsaturated hydrocarbons
Saturated Hydrocarbons
A hydrocarbon in which the carbon atoms are connected by only single bonds is called saturated hydrocarbon, e.g., methane (CH4), ethane (C2H6), propane (C3H8) and butane (CH10). These are also called as alkanes.
The general formula of alkanes or saturated hydrocarbons is CnH2n+2. Where n is the number of carbon atoms.
Unsaturated Hydrocarbons
A hydrocarbon in which the two carbon atoms are connected by a double bond or a triple bond is called an unsaturated hydrocarbon.
Types of Unsaturated Hydrocarbons
Unsaturated hydrocarbons are of two types:
1. Alkenes
An unsaturated hydrocarbon in which the two carbon atoms are connected by a double bond is called an alkene. For example,
| Name | Molecular Formula | Structural Formula |
| Ethene | C2H4 |  |
The general formula of an alkene is CnH2n where n is the no. of carbon atoms.
2. Alkynes
An unsaturated hydrocarbon in which the two carbon atoms are connected by a triple bond is called an alkyne. For example,
| Name | Molecular Formula | Structural Formula |
| Ethyne | C2H2 |  |
The general formula of an alkyne is CnH2n-2 where n is the no. of carbon atoms.
Test your understanding and answer these questions:
- What are hydrocarbons?