Final answer:
The bond type in compounds is determined by the electronegativity difference between the two atoms involved in the bond, which can identify the bond as covalent (polar or nonpolar) or ionic.
Step-by-step explanation:
The information used to determine each bond type in compounds, whether it's ionic or covalent, is based on A) Electronegativity difference. The absolute value of the difference in electronegativity of the two atoms involved in a bond provides an indication of the bond's polarity and hence its type. When this difference is very small or zero, the bond is covalent and nonpolar. Conversely, when the difference is large, the bond is likely to be polar covalent or ionic. For instance, the bonds H-H, H-Cl, and Na-Cl have electronegativity differences of 0 (nonpolar covalent), 0.9 (polar covalent), and 2.1 (ionic), respectively.