Question

The Formula of a compound of Radium is ${\mathrm{RaBr}}_2$. Write the formula of Radium Sulphate.

Answer 1

The Given Compound of Radium is ${\mathrm{RaBr}}_2$

We know, that the oxidation state of Halogens (Group 17 in the periodic table) is always $-1$.

The Oxidation state of Radium (Ra) in ${\mathrm{RaBr}}_2$ is $+2$ as the Oxidation state of Bromine(Br) is $-1$

The chemical formula of the Sulphate ion is ${\left({\mathrm{SO}}_4\right)}^{2-}$

Hence, the Oxidation state of the Sulphate ion is $-2$

The Compound Formed Must be neutral.

That is the net charge of the compound must be zero.

Hence, in order to neutralize the compound, one atom of Radium Requires one Sulphate ion

Thus, The Formula of the compound is ${\mathrm{RaSO}}_4$