Question

what property causes covalent compounds to be brittle? strong metallic bonds high flexibility strong ionic bonds weak intermolecular forces

Explanation:

Covalent compounds are made up of molecules held together by weak intermolecular forces. When a force is applied, these weak forces are easily overcome, causing the compound to break and be brittle. Metallic bonds (in metals), ionic bonds (in ionic compounds), and high flexibility (opposite of brittleness) are not relevant to the brittleness of covalent compounds.

Answer:

weak intermolecular forces