Question

The $\pi $-bonds are formed by the ____________ overlap of ____________ orbitals.

Answer 1

Hint:There are different types of molecular orbitals formed by the overlap of the atomic orbitals. Some are formed by the sidewise overlap while some are formed by the head-on overlap of the orbitals.

Complete answer:
There are different types of bonding among the atoms of the elements and molecules of the compounds. Among these, the covalent bonds are formed by the overlap of atomic or hybrid orbitals to share an electron pair to attain the octet configuration. The covalent bonds can be formed by either the head-on overlap of atomic or hybrid, or the sidewise overlap of the atomic orbitals. The head-on overlap of the atomic or hybrid orbitals leads to the formation of the sigma bonds, while the sidewise overlap of the atomic orbitals leads to the formation of the pi-bonds. The strength of the sigma bonds is higher in comparison to the strength of the pi-bonds as the area of overlap is higher in the former case and also the bond length is smaller.

Hence, the answer is: $\pi $-bonds are formed by the “side-wise” overlap of “${\text{p}}$atomic” orbitals.

Note:
The reason for the ${\text{p}}$ atomic orbitals forming the pi-bonds is that they lie along the axes and it is vertical so it is easier for the orbitals to overlap symmetrically. The pi bond looks like a cloud of electrons above and below the plane of the molecule formed. Common examples of the pi-bonding include the alkenes, alkynes, and aromatic compounds.