If the boron nitride molecule, bn, were to form, what would its structure look like? add bonds and lone pairs as necessary.

The structure for the boron nitride molecule will be linear.

Explanation: When boron and nitrogen combine together to form a compound, the boron element will loose 3 electrons which will be easily accepted by the nitrogen element.

Boron : Atomic number is 5

Electronic configuration:

To attain stable configuration, boron will loose 3 electrons easily.

Nitrogen : Atomic number is 7

Electronic configuration:

To attain stable configuration. nitrogen will gain 3 electrons easily.

Hence, to form a molecule with these two elements, there will be 3 bonds present in between them and 1 pair of lone pair will be left on the nitrogen atom.

Structure of boron nitride ( which is linear) is attached in the image below.

thats how its supposed to be