What is the chemical formula for Nitrogen?

The correct answer is B, N2, because nitrogen exists naturally as a diatomic molecule, meaning two nitrogen atoms bond together to form a single molecule of nitrogen gas. This form is prevalent in the atmosphere, which is composed of approximately 78% nitrogen, primarily in its diatomic form.

The single atom form, represented as N, does not accurately reflect how nitrogen typically exists under standard conditions, as it is almost always found as N2. The other options refer to different chemical compounds entirely; O2 is the formula for oxygen gas, and CO2 represents carbon dioxide, neither of which pertains to nitrogen.