Separate $1.0\,\text{g}$ portions of $\text{Na}_2\text{O}$, $\text{MgO}$, $\text{Al}_2\text{O}_3$, $\text{SiO}_2$, $\text{NaCl}$, $\text{MgCl}_2$, $\text{Al}_2\text{Cl}_6$ and $\text{SiCl}_4$ are each placed into different beakers that contain water and then stirred. The number of beakers that contain a white solid is $Q$. An excess of $\text{NaOH(aq)}$ is then introduced into each beaker and the mixtures are stirred again. The number of beakers that now contain a white solid is $R$. Which row is correct?
Chemistry 9701 · AS & A Level · The Periodic Table: chemical periodicity