Final answer:
The compound type depends on the difference in electronegativity. NaCl forms an ionic bond, HCl forms a polar covalent bond, and Cl2 forms a nonpolar covalent bond.
Step-by-step explanation:
To predict the kind of compound formed by atoms with different electronegativities, you can compare their values to determine the type of bond formed. If the difference in electronegativity (Δx) is greater than approximately 1.7, a complete electron transfer occurs, typical of ionic compounds.
Using the given electronegativities, Na (0.9), H (2.1), and Cl (3.0), we find:
- For NaCl, Δx is 3.0 - 0.9 = 2.1. This indicates a strong ionic bond as Na transfers its valence electron to Cl, forming Na+ and Cl- ions.
- For HCl, Δx is 3.0 - 2.1 = 0.9. This means that the bonding electrons are more strongly attracted to Cl, resulting in a polar covalent bond.
- For Cl2, Δx is 3.0 - 3.0 = 0. This results in a nonpolar covalent bond as the electrons are shared equally between the two Cl atoms.