Question

Atoms share electrons unequally in a(n) ________ bond. a. ionic b. hydrogen c. polar covalent d. nonpolar covalent

Short answer

Polar covalent bond.

Step-by-step solution

Understand the Nature of Each Bond

To determine the correct type of bond where electrons are shared unequally, first understand the characteristics of each bond type listed in the options. An ionic bond occurs when electrons are transferred between atoms. A hydrogen bond is an intermolecular force between molecules, not a true bond forming or sharing electrons within a single molecule. A covalent bond involves the sharing of electron pairs between atoms, with differences occurring in how equally these electrons are shared.

Identify the Nature of Unequal Sharing

Covalent bonds can be classified into polar and nonpolar. In nonpolar covalent bonds, electrons are shared equally between the atoms. In contrast, in polar covalent bonds, electrons are shared unequally due to differences in electronegativity between the bonded atoms. The more electronegative atom attracts the shared electrons more, resulting in partial charges on the atoms.

Analyze Each Option

Evaluate the four options with the identified information in mind: - a. Ionic bonds don't involve sharing but transferring of electrons. - b. Hydrogen bonds are not formed by sharing electrons. - c. Polar covalent bonds involve sharing electrons unequally. - d. Nonpolar covalent bonds involve equal sharing of electrons.

Determine the Correct Answer

Based on the analysis, only polar covalent bonds involve the unequal sharing of electrons. Thus, the answer is option c, polar covalent bonds.

Key concepts

Ionic Bonds

Ionic bonds are a type of chemical bond formed when one atom transfers electrons to another atom. This typically occurs between a metal and a non-metal. In this kind of bond, the metal atom loses one or more electrons to become a positively charged ion, while the non-metal atom gains those electrons to become a negatively charged ion.

• The attraction between these oppositely charged ions results in the formation of the ionic bond.
• These bonds are usually very strong, leading to the formation of crystalline structures such as salt.
• Ionic compounds tend to have high melting and boiling points due to the strength of the bonds.
• These compounds often dissolve in water and conduct electricity when dissolved or molten.

Covalent Bonds

Covalent bonds occur when two atoms share pairs of electrons. This bond forms usually between non-metal atoms. Unlike ionic bonds, there is no complete transfer of electrons, but instead, sharing occurs.

• The shared electrons allow each atom to achieve a stable electron configuration, similar to noble gases.
• Covalent bonds can vary in strength and length, being influenced by the sharing of one, two, or three pairs of electrons, known as single, double, or triple bonds respectively.
• These bonds form molecules and can include elements like oxygen (O₂) and hydrogen (H₂).

Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electrons within a bond. It plays a crucial role in determining the nature of bonds between atoms.

• When one atom is significantly more electronegative than another, it will attract the shared electrons more strongly.
• This difference in electronegativity can lead to unequal sharing of electrons, resulting in a polar covalent bond.
• Electronegativity values help predict the type of bond:
  • If the difference is large, the bond is likely to be ionic.
  • If the difference is moderate, a polar covalent bond forms.
  • If the difference is small or nonexistent, the bond is nonpolar covalent.

Polar Covalent Bonds

Polar covalent bonds are a specific type of covalent bond where the shared electrons are distributed unequally between the atoms due to differences in electronegativity. This results in a dipole moment, where one end of the molecule is slightly negative and the other end is slightly positive.

• A classic example of a polar covalent bond is the bond between hydrogen and oxygen in a water molecule (H₂O).
• In this bond, oxygen is more electronegative than hydrogen, so it attracts the shared electrons more strongly, creating a partial negative charge on the oxygen.
• The hydrogen atoms, being less electronegative, have a partial positive charge.
• Polar covalent bonds are essential in creating the unique properties of many substances, especially important in biological molecules.