How many formula units are present in 40.0 grams of Cu2S?

Never mind, I did the problem wrong, I deeply apologize.

answer; ///i do believe that the correct answer is (b); ///particle composed of two or more atoms bonded together;

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.