Valency of Iron (Fe)
Iron shows variable valency — most commonly 2 and 3 — because it is a d-block element whose outer electrons can join bonding in more than one way.
Teachers call it "one fact, fully handled" — exactly what this page does for Iron. The answer sits at the top in bold; scroll for the working, the shell-by-shell breakdown and the two questions students ask most. Need the whole picture instead — history, characteristics, uses, exam questions? The full Iron page is one click away.
Counting the valence electrons
From the configuration [Ar] 3d^6 4s^2, Iron's outermost shell carries 2 electrons. For a d-block element the nearby inner "d" subshell can also lend electrons, which is where variable valency comes from.
Position check: Iron belongs to group 8 of the periodic table, period 4.
Why Iron has more than one valency
The common valencies are 2 and 3. Both the outer s electrons and the nearby (n−1)d electrons sit close in energy, so Iron can offer different numbers of them in different compounds — giving ions such as Fe²⁺ and Fe³⁺ and families of compounds like FeX / Fe₃X₂.
Valency vs valence electrons
Valence electrons are what you count (2 for Iron); valency is what the atom will do to complete its outer shell (2 and 3 here). Keep the two words straight and half the periodic-table chapter writes itself.
Students also ask
How do I find the valency of Iron from its group?
Iron sits in group 8; for this transition group the safe exam answer is its common valency, 2 and 3.
Why does Iron show variable valency?
Because both its outer shell and the nearby inner subshell can participate in bonding, Iron forms more than one stable ion — hence valencies 2 and 3.