If two atoms bonded together have an electronegativity difference of 1.9, which type of bond is most likely formed, and what can be said about the dipole moment?

• A. An ionic bond is formed, and the molecule will have no dipole moment.
• B. A metallic bond is formed, and the molecule will have a small dipole moment.
• C. A nonpolar covalent bond is formed, and the molecule will have no dipole moment.
• D. A polar covalent bond is formed, and the molecule will have a significant dipole moment.

Answer: (D)

Verified step by step guidance

1. Understand that electronegativity difference between two bonded atoms helps predict the bond type: small differences usually indicate covalent bonds, large differences indicate ionic bonds.
2. Recall the general electronegativity difference ranges: 0 to about 0.4 for nonpolar covalent bonds, 0.5 to 1.7 for polar covalent bonds, and greater than about 1.7 for ionic bonds.
3. Given an electronegativity difference of 1.9, recognize that this value is slightly above the typical cutoff for ionic bonds, suggesting the bond is highly polar covalent or ionic in character.
4. Understand that polar covalent bonds result in an uneven distribution of electron density, creating a dipole moment where one atom has a partial negative charge and the other a partial positive charge.
5. Conclude that with a difference of 1.9, the bond is best described as polar covalent with a significant dipole moment, meaning the molecule has a measurable separation of charge.