Final answer:
The combination of 4 mol Na and 4 mol Br₂ forms the chemical compound NaBr, which is option D. This is because sodium and bromine ions combine in a 1:1 ratio, resulting in the formation of sodium bromide.
Step-by-step explanation:
The question concerns the combination of sodium (Na) and bromine (Br₂) to form a chemical compound. Given 4 mol of Na and 4 mol Br₂, the correct chemical formula would be NaBr because sodium forms +1 cations and bromine forms -1 anions, resulting in a 1:1 ratio of sodium ions to bromide ions when they combine to form an ionic compound. Therefore, for every mole of sodium, there will be one mole of bromide ions in the compound, not considering any complex stoichiometry or formation of polyatomic bromide species which does not typically occur with these elements. The correct answer is D. NaBr.
Example Reactions:
- 2Na (s) + Br₂ (g) → 2NaBr (s) - This equation shows sodium reacting with diatomic bromine to form sodium bromide.
- NaBr(s) dissociating in water: NaBr (s) → Na⁺ (aq) + Br⁻ (aq)
When writing chemical equations, it's important to consider the oxidation numbers and the fact that certain elements, such as bromine, exist as diatomic molecules in nature (H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂).