Final answer:
The representative particle for sodium sulfide is Na2S (Option B).
Step-by-step explanation:
The representative particle for sodium sulfide is represented by the formula Na2S (Option B). In this compound, two sodium ions (Na+) combine with one sulfide ion (S2-) to form an ionic compound. The formula NaS (Option D) represents sodium sulfide, but it does not account for the correct ratio of sodium ions to sulfide ions.