Chapter U2.16, Problem 1E

Interpretation Introduction

Interpretation : Difference between a polar covalent bond and a nonpolar covalent bond is to be explained.

Concept Introduction :

A covalent bond is formed when there is sharing of electrons between the atoms takes place to fulfill the octet configuration. There are two types of covalent bonds; polarcovalent bonds and nonpolarcovalent bonds.

Answer to Problem 1E

When two atoms with different electronegativities form a covalent bond with each other, the resultant bond is called polar covalent bond. Example: HCl has polar covalent bond between hydrogen atom and chlorine atom.

When the electronegativities of the atoms that bond are identical, the resultant bond is a nonpolar covalent bond. Example: O₂has nonpolar covalent bond between two oxygen atoms.

Explanation of Solution

In a polar , the bonded pair of electrons is not shared equally among the atoms. For example in HCl molecule, the hydrogen and chlorine atom do not share the bonded pair of electrons equally. The tendency of an atom to attract shared electrons is called electronegativity. Atom with higher electronegativity attracts more electrons than atom with low electronegativity. Atoms that are more electronegative have partial negative charge and atoms that are less electronegative have positive charge. This results in formation of a polar covalent bond.

If in a molecule the electronegativity of both the atoms is equal or identical, there is no pulling of electrons and they share the electrons equally between them. There is no formation of partial charges and this type of bond is called nonpolar covalent bond. In oxygen or hydrogen molecule, both atoms are same so they have no difference in electronegativity. Hence the bond is nonpolar covalent.

Conclusion

In a polar molecule one atom is more electronegative than other atom. In a nonpolar molecule both atoms have equal electronegativities.