Identify the intermolecular force, or forces that predominate in Al2O3 (check all that apply)

Group of answer choices

1. ionic

2. H-bonding

3. dispersion

4. dipole dipole

Well, Al2O3 is primarily held together by ionic bonds. So, ionic forces are definitely at play here. As for the other options: H-bonding typically involves hydrogen atoms bonded to highly electronegative elements like oxygen, nitrogen, or fluorine, which is not the case in Al2O3. Dispersion forces and dipole-dipole interactions are more commonly observed in molecules with polar covalent bonds, rather than in Al2O3, which has primarily ionic character. So, the answer is:

1. Ionic

The intermolecular force that predominates in Al2O3 is ionic bonding.

To identify the intermolecular forces that predominate in Al2O3, or aluminum oxide, we can use the Lewis structure of the compound as a starting point.

Aluminum oxide (Al2O3) is an ionic compound, meaning it consists of charged ions held together by electrostatic forces. In Al2O3, there are two aluminum ions (Al3+) and three oxide ions (O2-). The aluminum ions have a 3+ charge, while the oxide ions have a 2- charge.

Since Al2O3 is ionic, the dominant intermolecular force is ionic bonding (choice 1). Ionic bonding is the electrostatic attraction between positively and negatively charged ions.

The other three intermolecular forces listed—H-bonding, dispersion, and dipole-dipole—are relevant for compounds that have covalent bonds, where electrons are shared between atoms. However, in the case of Al2O3, the bonding is predominantly ionic rather than covalent, and so the forces associated with covalent compounds (H-bonding, dispersion, and dipole-dipole) play a minor role, if any at all.

Therefore, the correct answer is choice 1: ionic.

You are calling these a "group of" answer choices but what you have listed are not groups but single answer choices.

If we call a difference of 1.7 the 50-50 ionic/covalent bond for electronegativity (EN), then this is more ionic than covalent (delta EN = 1.9) so ionic is one, dipole-dipole is another. There are no H bonds. There are dispersion forces in anything but dispersion forces are weak so I wouldn't count those as predominate.