Question

the structure of one form of boron nitride is represented above. this form of boron nitride is one of the hardest substances known. which of the following best helps explain why boron nitride is so hard? a boron ions and nitrogen ions are held together by ionic bonds. b boron nitride is a network solid of atoms connected by covalent bonds with fixed bond angles. c boron nitride is an alloy, and alloys are typically harder than the elements used to make them.

Explanation:

Boron nitride is a network - solid with atoms connected by strong covalent bonds. Covalent bonds are difficult to break, which contributes to its hardness. Option A is incorrect as it is not an ionic - bonded structure. Option C is wrong because boron nitride is not an alloy.

Answer:

B. Boron nitride is a network solid of atoms connected by covalent bonds with fixed bond angles.