Question

ammonium sulfide is a polyatomic ionic compound. when applied to bronze, ammonium sulfide reacts with the metal to produce a bluish - black tarnish, or patina. write the chemical formula for ammonium sulfide. refer to a periodic table and a list of polyatomic ions.

Explanation:

Step1: Identify the ions

Ammonium ion is $NH_4^+$ and sulfide ion is $S^{2 - }$.

Step2: Determine the ratio for charge - neutrality

To balance the charges, we need 2 ammonium ions for every 1 sulfide ion since the charge on ammonium is + 1 and on sulfide is - 2.

Answer:

$(NH_4)_2S$