Final answer:
The difference of electronegativity values between two bonded atoms serves as an indicator of the bond's ionic character, influencing whether the bond is nonpolar covalent, polar covalent, or ionic.
Step-by-step explanation:
Generally, you can take the difference of electronegativity values between two atoms of a bond to be a rough measure of the bond's ionic character. This difference is represented by the formula ΔX = XB - XA, where ΔX indicates the difference in electronegativity, XB is the electronegativity of atom B, and XA is that of atom A.
The scale of this difference determines the bond type; with a very small or zero difference indicating a nonpolar covalent bond and a larger difference suggesting a polar covalent or ionic bond. For instance, the electronegativity difference in the bonds H-H, H-Cl, and Na-Cl demonstrates this principle with values of 0 (nonpolar covalent), 0.9 (polar covalent), and 2.1 (ionic), respectively. As the difference increases, so does the bond polarity and ionic character of the bond.
Although electronegativity values can be difficult to measure precisely and may vary slightly depending on the method, the concept is valuable for estimating the polarity of a bond in chemical bonds.