Sunday, June 27, 2010

Organic Chemistry - Basic Concepts, Points, and Principles

1. Modern definition of the organic chemistry: Chemistry of the hydrocarbons and their derivatives.

2. Catenation: property of an atom to form bonds with atoms of the same element is called catenation. Carbon shows maximum catenation in its group (group 14) in the periodic table. Hence carbon atoms form linear chains, branched chains and rings of different sizes.

3. Sigma and Pi bonds: When there is a double bond between two carbon atoms, one is a sigma bond and one is Pi bond.

4. Organic compounds are represented by structural formula, bond line structural representation.
5. Three dimensional representations of organic compounds include solid and dash wedged formula, Fischer projection, Newmann projection, Sawhorse projection formulae etc.
6. Models can be employed to visualize bonds of organic compounds. There are framework models, ball and stick model, and space filling model.
7. Functional group: Functional groups of structural features within a molecule that determine its reactivity. Thus a functional group is a group of atoms within a molecule that has a charateristic chemical behaviour. For illustration, the simplest functional group is the carbon-carbon double bond. Similarly carbon-carbon triple bond will be another functional group.
8. The important functional groups are:
Alkyl halide, Alcohols, Ethers, Amines, Thiol, Aldehyde, Ketone, Carboxylic acids, Esters, Acid halides, Amides, Nitriles.
9. Homologous Series: A series of similarly constituted compounds containing the same functional group and hae similar chemical charateristics.
10.Nomenclature of organic compounds: There are two systems. In trivial system, the organic compounds were named after the source from which they were obtained and other bases are also used. There is no systematic basis. IUPAC (International Union of Pure and Applied Chemistry) developed a system of nomenclature.
11. Isomerism: Organic compounds exhibit isomerism. Isomerism is a phenomenon that describes the fact two compounds having same molecular formula have different physical and chemical properties.
12. Structural isomerism and stereo isomerism are two major categories in isomerism.
13. Benzene ring: Benzene is an organic compound that is represented as having six carbon atoms in the form of a hexagon with three double bonds in the alternative positions. It molecular formula is C6H6.
14. Aromatic compounds are those which contain one or more benzene rings in them. Aromatic compounds have two main parts. Nucleus, the benzene ring and an alkyl or aliphatic group containing at least one carbon atom attached to the nucleus.
15. The organic compounds which contain only hydrogen and carbon are hydrocarbons.
16. Hydrocarbons are broardly divided into four types. 1. Alkanes 2. Alkenes 3. Alkynes 4. Arenes
17. In alkanes, there are only carbon-carbon single bonds. Both open chain and closed chain (ring) alkanes are there.
18. In alkenes, there are carbon-carbon double bonds apart from some double bonds.
19. In alkynes, there are carbon-carbon triple bonds apart from single or double bonds.
20. Arenes have at least one special type of hexagonal ring of carbon atoms with three double bonds and three single bonds in alternative positions. The ring is called benzene ring.

To be continued and more points to be added.