Question

An element $\mathrm{Z}$ has a valency of $4$. Write the formula for its carbonate

Answer 1

It is given that the valency of an element $\mathrm{Z}$ is $4$, the formula for its carbonate is:

$$\begin{gathered} \mathrm{Symbol}\mathrm{Z}{\mathrm{CO}}_3 \\ \searrow \swarrow \\ \mathrm{Valency}4-2 \end{gathered}$$

As the valency of the carbonate ion is $-2$, by applying the criss-cross method the molecular formula of the compound is ${\mathrm{Z}}_2{\left({\mathrm{CO}}_3\right)}_4\mathrm{or}\mathrm{Z}{\left({\mathrm{CO}}_3\right)}_2$