📚 Topic Summary
Bond polarity arises from the unequal sharing of electrons between atoms in a chemical bond. This unequal sharing occurs when there is a difference in electronegativity between the bonded atoms. The atom with the higher electronegativity attracts electrons more strongly, resulting in a partial negative charge ($\delta^-$) on that atom and a partial positive charge ($\delta^+$) on the other atom. A bond dipole moment arises, which is a measure of the polarity of the bond.
If the electronegativity difference is large (typically greater than 1.7), the bond is considered ionic, where electrons are essentially transferred from one atom to another. If the electronegativity difference is small (less than 0.4), the bond is considered nonpolar covalent, where electrons are shared relatively equally. Between these values, the bond is considered polar covalent.
🧪 Part A: Vocabulary
Match the term with the correct definition:
| Term |
Definition |
| 1. Electronegativity |
A. A measure of the polarity of a chemical bond. |
| 2. Polar Covalent Bond |
B. The ability of an atom to attract electrons in a chemical bond. |
| 3. Nonpolar Covalent Bond |
C. A bond where electrons are shared unequally between atoms. |
| 4. Bond Dipole Moment |
D. A bond where electrons are shared equally between atoms. |
| 5. Partial Charge |
E. The slight positive or negative charge on an atom in a polar bond, denoted by δ+ or δ-. |
⚗️ Part B: Fill in the Blanks
Complete the following paragraph with the correct terms:
A _______ bond occurs when electrons are shared unequally between two atoms due to a difference in ________. The atom with the higher value will have a partial _______ charge, represented by the symbol $\delta^-$. This creates a _______ moment, indicating the bond's polarity. Conversely, in a _______ bond, electrons are shared nearly equally.
🤔 Part C: Critical Thinking
Explain how the concept of bond polarity helps predict the overall polarity of a molecule. Provide an example.