A covalent bond is formed by the equal sharing of electrons from both the participating atoms. The pair of electrons participating in this type of bonding is called shared pair or bonding pair.
Polar covalent bond
The polar covalent bond is a type of covalent bond formed between two non-identical atoms.
- Since the two atoms differ in their capacity to attract the shared electron pair unequal sharing of electrons results.
- Due to the unequal sharing of electrons, fractional positive and negative charges are developed on the bonded atoms and the bond is said to be polar.
- Polar covalent bonding is a type of chemical bond where a pair of electrons is unequally shared between two atoms due to the difference in their electro-negativities. These compounds are called polar covalent compounds. An example is HCl, where both have different electro-negativities.
Non-polar covalent bond
This type of covalent bond is formed whenever there is an equal share of electrons between atoms.
- The electronegativity difference between two atoms is zero.
- It occurs wherever the combining atoms have similar electron affinity such as diatomic elements.
- Nonpolar Covalent Bond is found in gas molecules like Hydrogen gas, Nitrogen gas, etc.
Constituent polar and nonpolar covalent compounds
Polar covalent bond – Formed between atoms having a difference in their electronegativities.
Eg. H2O, HI, HCl, NH3.
Non-polar covalent bond – Formed by identical atoms. Eg.Cl2, O2, N2, etc.
Covalent bonds formed between atoms of the same kind are usually non-polar and the shared electrons are equidistant from both atomic nuclei. Polar covalent bonds are charged (positive as well as negative poles), whereas non-polar covalent bonds are not charged.