Polar Covalent Bonds
Polar covalent bonding is a type of chemical bonding where a pair of electrons is unequally shared between two atoms. In other words, the distribution of electrons around the molecule is no longer balanced. This is due to one of the elements having a higher electronegativity than the other. Atoms with high electronegativity values such as fluorine, oxygen and nitrogen exert a greater pull on electrons than do atoms with lower electronegativity values. In a bond, this can lead to unequal sharing of electrons between atoms as electrons will be drawn closer to the atom with higher electronegativity.
In a polar covalent bond also referred to as polar bond, the atom with the greater electronegativity acquires a partial negative charge whereas the atom with the lesser electronegativity acquires a partial positive charge. Polar covalent bonds form more often when atoms that differ greatly in size share electrons.
Water molecule is an example of a polar covalent bond. The electrons are unequally shared, with the oxygen atom having a greater pull on electrons than the hydrogen atoms. Since electrons are drawn closer to oxygen atom, it carries a partial negative charge. Another example of a polar covalent bond is between a hydrogen and chlorine atom. In this bond, the chlorine atom, chlorine has a greater pull on electrons than the hydrogen atom. Because of this unequal sharing of electrons, the chlorine atom carries a partial negative charge and the hydrogen atom carries a partial positive charge.
What You Need To Know About Polar Covalent Bonds
- Polar covalent bonding is a type of chemical bonding where a pair of electrons is unequally shared between two atoms.
- Polar covalent bond results in the formation of opposite partial charges on the bonded atoms which is called dipole.
- Polar covalent bond is formed between atoms of different elements.
- Polar covalent bonds are relatively weak when compared nonpolar covalent bonds.
- Molecules with polar covalent bonds have a greater melting and boiling point than non-polar covalent.
- Molecules with polar covalent bonds conduct electricity in solution state due to free mobility of ions.
- Molecules with polar covalent bonds are highly soluble in polar solvents like water.
- Molecules with polar covalent bonds have permanent dipole moment.
- Examples of molecules with polar covalent bond include: Water (H2O), Hydrogen Fluoride (HF) and ammonia (NH3).
Nonpolar Covalent Bonds
Nonpolar covalent bond is a type of bond that occurs when two atoms share a pair of electrons with each other. In a Nonpolar covalent bond, the distribution of electrical charge is balanced between the two atoms.
An example of a nonpolar covalent bond is the bond between two hydrogen atoms because they equally share the electrons. Another example of a nonpolar covalent bond is the bond between two chlorine atoms because they also equally share the electrons. Nonpolar covalent bonds are very strong bonds requiring a large amount of energy to break the bond.
Another example of a nonpolar covalent bond is found in the methane (CH4) molecule. The carbon atom has four electrons in its outermost shell and needs four more to fill. It gets these four from four hydrogen atoms, each atom providing one. These elements all share the electrons equally, creating four nonpolar covalent bonds.
What You Need To Know About Nonpolar Covalent Bonds
- Nonpolar covalent bond is a type of bond that occurs when two atoms share a pair of electrons with each other.
- Non-polar covalent bond does not result in charge separation between bonded atoms.
- Non-polar covalent is formed between atoms of same element.
- Nonpolar covalent bonds are very strong bonds requiring a large amount of energy to break the bond.
- Molecules with Nonpolar covalent bonds have a relatively low melting and boiling point than non-polar covalent since they don’t have any interaction or polarity.
- Molecules with Nonpolar covalent bonds do not conduct electricity since they have no chargeable particles.
- Molecules with Nonpolar covalent bonds are insoluble in water or less soluble in water. However, they are more soluble in nonpolar solvents like CCl4, CHCl3 etc.
- Molecules with polar covalent bonds have zero dipole moment.
- Examples of molecules with nonpolar covalent bond include: He, Ne, Ar, Benzene, H2, O2, Cl2, Methane and carbon dioxide.
Also Read: Difference Between Polar And Non-polar Molecules
Difference Between Polar And Nonpolar Covalent Bonds In Tabular Form
BASIS OF COMPARISON | POLAR COVALENT BOND | NONPOLAR COVALENT BOND |
Description | It is a type of chemical bonding where a pair of electrons is unequally shared between two atoms. | It is a type of bond that occurs when two atoms share a pair of electrons with each other. |
Charges | It results in the formation of opposite partial charges on the bonded atoms which is called dipole. | It does not result in charge separation between bonded atoms. |
Formation | It is formed between atoms of different elements. | It is formed between atoms of same element. |
Strength | They are relatively weak when compared Nonpolar covalent bonds. | They are very strong bonds requiring a large amount of energy to break the bond. |
Boiling & Melting Point | Molecules with polar covalent bonds have a greater melting and boiling point than non-polar covalent. | Molecules with Nonpolar covalent bonds have a relatively low melting and boiling point than non-polar covalent since they don’t have any interaction or polarity. |
Conductivity | Molecules with polar covalent bonds conduct electricity in solution state due to free mobility of ions. | Molecules with Nonpolar covalent bonds do not conduct electricity since they have no chargeable particles. |
Solubility | Molecules with polar covalent bonds are highly soluble in polar solvents like water. | Molecules with Nonpolar covalent bonds are insoluble in water or less soluble in water. However, they are more soluble in Nonpolar solvents like CCl4, CHCl3 etc. |
Dipole Moment | Molecules with polar covalent bonds have permanent dipole moment. | Molecules with polar covalent bonds have zero dipole moment. |
Examples | Water (H2O), Hydrogen Fluoride (HF) and ammonia (NH3). | He, Ne, Ar, Benzene, H2, O2, Cl2, Methane and carbon dioxide. |
Also Read: Difference Between Covalent And Ionic Bonds