Chemistry

Problem

A diagram of an ionic solid contains discrete groups in which two gray spheres labeled

\mathrm{Al}^{3+}

are closely associated with three sulfate polyatomic ions (each modeled as one yellow sphere surrounded by four red spheres and carrying a

2-

charge). No other ions are present. Which chemical formula is most consistent with the diagram? a)

\mathrm{Al_3(SO_4)_2}

\mathrm{Al_2(SO_4)_3}

\mathrm{Al_2(SO_4)}

\mathrm{Al(SO_4)_3}