CBSE Class 11-science Answered

When a carbon atom forms a compound, it always forms covalent bonds. There are two types of covalent bonds : sigma and pi bond. When the covalent bonds are linear or aligned along the plane containing the atoms, the bond is known as sigma () bond. Sigma bonds are strong and the electron sharing is maximum. Methane CH₄ is a good example for sigma bond and it has four of them. 

When the electron orbitals overlap laterally, the bond is called the pi () bond. In pi bonds the resulting overlap is not maximum and these bonds are relatively weak. A molecule of ethylene or ethene (C₂H₄) has 4 bonds and 2   bonds.  In pi bonds the resulting overlap is not maximum and these bonds are relatively weak. A molecule of ethylene or ethene (C₂H₄) has 4  bonds and 2  bonds.  

            Pi () bond