## Chemistry: Principles and Practice (3rd Edition)

The answer is option (b). In water, lithium sulfide (Li$_2$S) will dissociate into two lithium ions (Li$^+$) and one sulfide ion (S$^{2-}$). Lithium and sulfur combine in a 2:1 ration; therefore, there should be two lithium atoms for every sulfur atom. The lithium ions are represented by the smaller white balls, and the sulfide ions are the bigger yellow balls because anions are usually larger than cations. The best representation of lithium sulfide in water is option (b).
In water, lithium sulfide will dissociate into two lithium ions (Li$^+$) and one sulfide ion (S$^{2-}$). Lithium and sulfur combine in a 2:1 ration; therefore, there should be two lithium atoms for every sulfur atom. The chemical formula for the compound is (Li$_2$S). The lithium ions are represented by the smaller white balls, and the sulfide ions are the bigger yellow balls because anions are usually larger than cations. The best representation of lithium sulfide in water is option (b).