The Nature of Bonding

When atoms come together to form compounds, they can do so by sharing, giving away, or receiving electrons. The way in which electrons are shared between atoms determines the type of bond that is formed. In the case of covalent bonding, electrons are shared between atoms, resulting in the formation of covalent bonds.

Covalent Bonding

Covalent bonding occurs when two atoms share a pair of electrons. This type of bonding is typically observed between nonmetal atoms. In a covalent bond, the electron pair is shared between the two atoms involved. However, it is important to note that the electron pair may not always be shared equally.

Polarity in Covalent Bonds

When electrons are not equally shared between two atoms in a covalent bond, the bond is said to be polar. This means that one atom has a partial negative charge (δ-) while the other has a partial positive charge (δ+). The unequal sharing of electrons occurs when one atom has a higher electronegativity than the other.

Electronegativity and Polar Covalent Bonds

Electronegativity is a measure of an atom's ability to attract electrons towards itself in a covalent bond. The electronegativity difference between two atoms can help determine the polarity of a covalent bond.

When the electronegativity difference between two atoms is small (less than 0.5), the bond is considered nonpolar covalent. In this case, the electron pair is shared equally between the atoms, resulting in a balanced distribution of charge.

However, when the electronegativity difference is moderate (between 0.5 and 1.7), the bond is considered polar covalent. In this case, the more electronegative atom pulls the electron pair closer to itself, resulting in a partial negative charge on that atom and a partial positive charge on the other atom.

Examples of Polar Covalent Bonds

One common example of a polar covalent bond is the hydrogen chloride (HCl) molecule. Chlorine is more electronegative than hydrogen, so it pulls the electron pair closer to itself, creating a partial negative charge on chlorine and a partial positive charge on hydrogen.

Another example is the water (H2O) molecule. Oxygen is more electronegative than hydrogen, so it attracts the electron pair closer to itself, resulting in a partial negative charge on oxygen and partial positive charges on the hydrogen atoms.

Conclusion

In summary, if the electron pair is not equally shared between two atoms in a covalent bond, the bond is considered polar covalent. This occurs when there is an electronegativity difference between the atoms involved. Polar covalent bonds result in a partial positive charge on one atom and a partial negative charge on the other atom. It is important to note that nonpolar covalent bonds exist when the electron pair is shared equally.

polar covalent bond , because in non -polar covalent bond electrons are shared unequally