Valency of Chromium (Cr)
Chromium shows variable valency — most commonly 2, 3 and 6 — because it is a d-block element whose outer electrons can join bonding in more than one way.
Looking for Chromium's valency without wading through a whole chapter? Here is the direct answer first, then the tables and derivations examiners want to see. Every number on this page comes from the same engine that powers the interactive table. Need the whole picture instead — history, characteristics, uses, exam questions? The full Chromium page is one click away.
Counting the valence electrons
From the configuration [Ar] 3d⁵ 4s¹, Chromium's outermost shell carries 1 electron. For a d-block element the nearby inner "d" subshell can also lend electrons, which is where variable valency comes from.
Position check: Chromium belongs to group 6 of the periodic table, period 4.
Why Chromium has more than one valency
The common valencies are 2, 3 and 6. Both the outer s electrons and the nearby (n−1)d electrons sit close in energy, so Chromium can offer different numbers of them in different compounds — giving ions such as Cr²⁺ and Cr³⁺ and Cr⁶⁺ and families of compounds like CrX / Cr₃X₂ / Cr₆X₂.
Valency vs valence electrons
Valence electrons are what you count (1 for Chromium); valency is what the atom will do to complete its outer shell (2, 3 and 6 here). Keep the two words straight and half the periodic-table chapter writes itself.
Students also ask
How do I find the valency of Chromium from its group?
Chromium sits in group 6; for this transition group the safe exam answer is its common valency, 2, 3 and 6.
Why does Chromium show variable valency?
Because both its outer shell and the nearby inner subshell can participate in bonding, Chromium forms more than one stable ion — hence valencies 2, 3 and 6.