discuss the concept of hybridisation.what are its different types in a carbon atom
Answers
Types of hybridisation in carbon atoms. a) i) Diagonal or sp-hybridisation: All compounds of carbon containing C≡C triple bond like ethyne (C2H2). ii) Trigonal or sp2 hybridisation All compounds of carbon containing C=C (double bond) like ethene (C2H4).
Explanation:
(i) Hybridisation: In order to explain the characteristic geometrical shapes of polyatomic molecules like CH4,NH3 and H2O etc., Pauling introduced the concept of hybridisation. According to him the atomic orbitals combine to form new set of equivalent orbitals known as hybrid orbitals. Unlike pure orbitals, the hybrid orbitals are used in bond formation. The phenomenon is known as hybridisation which can be defined as the process of intermixing of the orbitals of slightly different energies so as to redistribute their energies, resulting in the formation of new set of orbitals of equivalent energies and shape.
For example, when one 2s and three 2p-orbitals of carbon hybridise, there is the formation of four new sp3 hybrid orbitals. The main features of hybridisation are as under:
1. The number of hybrid orbitals is equal to the number of the atomic orbitals that get hybridised.
2. The hybridised orbitals are always equivalent in energy and shape.
3. The hybrid orbitals are more effective in forming stable bonds than the pure atomic orbitals.
4. These hybrid orbitals are directed in space in some preferred direction to have minimum repulsion between electron pairs and thus a stable arrangement.
Therefore, the type of hybridisation indicates the geometry of the molecules.
Different types of hybridisation in carbon atom are:
• In carbon compounds, if carbon is linked to carbon through triple bond, e.g. Alkynes,
Triple bonded carbon is sp hybridised.
• In carbon compounds, if carbon is linked to carbon through double bond (C=C), e.g., Alkenes,
Double bonded carbon is sp2 hybridised.
• In carbon compounds, if carbon is linked to carbon through single bond (C—C), e.g., Alkanes,
Single bonded carbon is sp3 hybridised.
(ii) Type of hybridisation: {refer above figure}
1. Both the atoms are sp2 hybridised.
2. Marked atom is sp3 hybridised
3. Marked atom is sp2 hybridised
4.Marked atom is sp3 hybridised
5. Marked atom is sp2 hybridised
