Question

Write the formula and valency of ferric.

Answer 1

Valency: Valency refers to the number of electrons that are gained or lost by an atom in order to complete its outermost shell.

Variable valency: Certain elements have more than one valency. They exhibit variable valency. For example, copper, tin, iron, and mercury exhibit variable valency.

The suffix “ous” is used to indicate the lower valency and the suffix “ic” to indicate the higher valency.

Since iron exhibits variable valencies, the formula of ferric is ${\mathrm{Fe}}^{3+}$ and its valency is +3.