(Solved): Which molecule contains only two distinct elements but 4 individual atoms? \[ \begin{array}{l} \mat ...

Which molecule contains only two distinct elements but 4 individual atoms? \[ \begin{array}{l} \mathrm{C}_{2} \mathrm{H}_{4} \\ \mathrm{Na}_{2} \mathrm{SO}_{4} \\ \mathrm{C}_{3} \mathrm{H}_{6} \\ \mathrm{CaSO}_{4} \\ \mathrm{AlCl}_{3} \end{array} \] What is the excess reactant in the above example? X Y XY