Question

What is the valency of iron in ferrous sulphate?

Answer 1

Valency:

• “Valency is the combining capacity of an atom.”
• “The electrons present in the outermost shell of an atom are known as the valence electrons.”

The valency of iron in ferrous sulfate:

• Iron in its +2 oxidation state and sulfate ions make up the chemical compound known as ferrous sulfate.
• ${\mathrm{FeSO}}_4$is its chemical composition.
• Iron's electronic configuration in the ground state:
• $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{6}4{\mathrm{s}}^2$
• After generating ferrous sulfate, iron is in its +2 electronic configuration.
• $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{6}4{\mathrm{s}}^0$
• Since iron has two electrons in its valence shell, these electrons join those of sulfate ions to produce ferrous sulfate.
• Iron in ferrous sulfate, therefore, has a valency of two.
• Heating ferrous sulfate causes it to change into an iron (III) compound, or show a valency of three, in order to attain its stable half-filled d-orbital configuration.
• This is because the half-filled and fully filled orbitals are more stable than partially filled orbitals.