Question

a. What is the meaning of the term polar, as applied to chemical bonding? b. Distinguish between polar-covalent and nonpolar-covalent bonds.

Short answer

Polar means unequal charge distribution in bonds. Polar-covalent bonds have partial charges due to unequal electron sharing, while nonpolar-covalent bonds share electrons equally with no partial charges.

Step-by-step solution

Title - Define Polarity in Chemical Bonding

Polarity in chemical bonding refers to the distribution of electrical charge over the atoms joined by the bond. In a polar bond, one atom has a slightly positive charge, while the other has a slightly negative charge.

Title - Explain Polar-Covalent Bonds

Polar-covalent bonds occur when two different atoms share electrons unequally. The difference in electronegativity between the two atoms causes one end of the bond to have a partial positive charge and the other to have a partial negative charge.

Title - Explain Nonpolar-Covalent Bonds

Nonpolar-covalent bonds occur when two identical atoms or atoms with very similar electronegativities share electrons equally. This results in a more even distribution of electrical charge, with no partial charges on either atom.

Title - Compare Polar-Covalent and Nonpolar-Covalent Bonds

The key distinction between polar-covalent and nonpolar-covalent bonds lies in the distribution of electron density. Polar-covalent bonds have unequal sharing of electrons and result in partial charges, while nonpolar-covalent bonds have equal sharing of electrons and no partial charges.

Key concepts

Polarity in Chemical Bonding

Polarity in chemical bonding is all about how electrons are distributed between atoms in a molecule. When atoms form a bond, they either share electrons equally or unequally, and this sharing pattern determines the bond's polarity. In a polar bond, electrons are shared unequally due to differences in electronegativity (more on that later). This unequal sharing results in one atom having a slightly positive charge and the other having a slightly negative charge. Think of it like a game of tug-of-war, where one side is stronger and pulls the rope closer to them.

Polar-Covalent Bonds

Polar-covalent bonds form between two different atoms that share electrons unequally. The reason for the unequal sharing is the difference in electronegativity between the two atoms.
Electronegativity is an atom's ability to attract and hold onto electrons.
When one atom is more electronegative, it pulls the shared electrons closer to itself, making one end of the bond slightly negative and the other end slightly positive.

• An example of a polar-covalent bond is the bond between hydrogen and oxygen in a water molecule (H2O).
• In this example, oxygen is more electronegative than hydrogen, making the electrons spend more time near the oxygen atom.
• The result is a molecule with a slight negative charge near the oxygen and a slight positive charge near the hydrogens.

This separation of charge within the molecule is what makes it polar.

Nonpolar-Covalent Bonds

Nonpolar-covalent bonds occur when two atoms share electrons equally. This typically happens between identical atoms or atoms with very similar electronegativities. In this case, the electron density is evenly distributed, and there are no partial charges on either atom.
Imagine a pair of identical twins sharing a toy; neither twin has more control over the toy than the other, so the sharing is equal.

• An example of a nonpolar-covalent bond is the bond between two hydrogen atoms in a hydrogen molecule (H2).
• Both hydrogen atoms have the same electronegativity, so they share the electrons equally.

Because of this equal sharing, nonpolar-covalent bonds do not create any partial charges in the molecule.