Question

Write the chemical formula for:

Iron (III) carbonate

Answer 1

Chemical formula of Iron (III) carbonate $\left[{\mathrm{Fe}}_2{\left({\mathrm{CO}}_3\right)}_3\right]$:

Step-1: Write the chemical symbol of the cation and anion.

• Here cation is Iron i.e; $\mathrm{Fe}$
• And anion or acidic radical is Carbonate i.e.; ${\mathrm{CO}}_3$

Step-2: Write the valency or charges of the cation and anion below their symbols

Valency of iron= 3 (given in the chemical name)

Valency of carbonate= 2

$$\begin{gathered} \mathrm{Symbol}\mathrm{Fe}{\mathrm{CO}}_3 \\ \mathrm{Valency}32 \end{gathered}$$

Step-3: Transpose the valency of cation with anion and vice versa using criss-cross method

Valency: Valency is the combining capacity of an atom of the element.

$$\begin{gathered} \mathrm{Symbol}\mathrm{Fe}{\mathrm{CO}}_3 \\ \searrow \swarrow \\ \mathrm{Valency}32 \end{gathered}$$

Step-4: Write the formula

$\left[{\mathrm{Fe}}_2{\left({\mathrm{CO}}_3\right)}_3\right]$