Question

The formula of radium bromide is ${\mathrm{RaBr}}_2$. Write the formula of Radium sulfite.

Answer 1

It is given that the formula of Radium bromide is ${\mathrm{RaBr}}_2$.

By applying the criss-cross method we can find the valency of Radium

$$\begin{gathered} \mathrm{Symbol}\mathrm{Ra}\mathrm{Br} \\ \searrow \swarrow \\ \mathrm{Valency}21 \end{gathered}$$

Thus, the valency of radium is found to be $2$

Now, the molecular formula of Radium sulfite can be determined by the criss-cross method:

$$\begin{gathered} \mathrm{Symbol}\mathrm{Ra}{\mathrm{SO}}_3 \\ \searrow \swarrow \\ \mathrm{Valency}22 \end{gathered}$$

Thus, the Molecular formula of Radium sulfite is ${\mathrm{Ra}}_2{\left({\mathrm{SO}}_3\right)}_2\mathrm{or}\mathrm{Ra}\left({\mathrm{SO}}_3\right)$.