Question

Which type of overlapping results in the formation of a π bond?
(A) Axial overlapping of s-s orbitals
(B) Lateral overlapping of p-p orbitals
(C) Axial overlapping of p-p orbitals
(D) Axial overlapping of s-p orbitals

Answer 1

Hint: Overlapping means a partial merging of the atomic orbitals. The strength of a covalent bond depends upon the extent of the overlapping of the atomic orbitals. The greater the overlapping of the two atomic orbitals, the stronger the bond formed and vice-versa. Depending upon the phase of the overlapping atomic orbitals, the overlapping can be positive (in phase), negative (out of phase), or zero overlapping.

Complete Step by Step Answer:
The atomic orbitals can overlap in two ways: axial overlapping and lateral overlapping. Two s-orbitals or one s and one p-orbital will overlap axially and will form a Sigma bond. Also, two p orbitals that overlap head-to-head will form a sigma bond, and if the two p orbitals overlap laterally, that is, the two axes remain parallel to each other and perpendicular to the internuclear axis, then they will form a pi bond.
Correct Option: (B) Lateral overlapping of p-p orbitals.

Note: Axial overlapping or head-to-head overlapping of the two atomic orbitals will always form a sigma bond. Lateral overlapping or sideways overlapping of the two atomic orbitals will always form a pi bond. Along with a pi bond, there is always a sigma bond. That is, if there is a double bond, then one bond will be a sigma bond and the other will be a pi bond. Similarly, if there is a triple bond, then one of the bonds is a sigma bond and the other two are pi bonds.