Question

How do you draw sigma and pi bonds?

Answer 1

Hint : A chemical bond formed by mutual sharing of electron pairs between the atoms is known as a covalent bond. These electron pairs are referred to as bonding pairs or a shared pair of electrons. The covalent bonds are directional i.e., atoms bonded via covalent bond are present in specific orientation with respect to one another.

Complete Step By Step Answer:
A covalent bond is broadly categorized into two types: sigma bond and pi bond. Let us discuss each type of covalent bond separately.
Sigma bond: A covalent bond which is formed as a result of formation of a molecular orbital by positive overlapping of atomic orbitals done by head-on-head or end-to-end overlapping. It is represented by a symbol $\sigma$. Possible illustrations for formation of a sigma bond are given below:
s-s overlapping:

p-p overlapping:

s-p overlapping:

${d_{{z^2}}} - {d_{{z^2}}}$ overlapping:

Pi bond: A covalent bond which is formed as a result of formation of a molecular orbital by positive overlapping of atomic orbitals done by side-to-side overlapping. It is represented by a symbol $\pi$. Possible illustrations for formation of a pi bond are given below:
p-p overlapping:

${d_{yz}} - {d_{yz}}$ overlapping:

${d_{xz}} - {d_{xz}}$ overlapping:

Note :
It is a general misconception that sigma bonds are formed by overlapping of s-orbitals only and the pi-bonds are formed by the overlapping of only p-orbitals but the fact is a sigma bond can be formed by head-on-head overlapping of any orbital, not just s-orbital. Also, remember that a single bond in covalent bonding always consists of only sigma bonds whereas in double and triple bonds, pi bonds are also present along with a sigma bond.