Valency of Uranium (U)
Uranium shows variable valency — most commonly 4 and 6 — because it is a f-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 Uranium. 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 Uranium page is one click away.
Counting the valence electrons
From the configuration [Rn] 5f³ 6d¹ 7s², Uranium's outermost shell carries 2 electrons. For a f-block element the nearby inner "f" subshell can also lend electrons, which is where variable valency comes from.
Position check: Uranium belongs to the f-block of the periodic table, period 7.
Why Uranium has more than one valency
The common valencies are 4 and 6. Both the outer s electrons and the nearby (n−1)d electrons sit close in energy, so Uranium can offer different numbers of them in different compounds — giving ions such as U⁴⁺ and U⁶⁺ and families of compounds like U₄X₂ / U₆X₂.
Valency vs valence electrons
Valence electrons are what you count (2 for Uranium); valency is what the atom will do to complete its outer shell (4 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 Uranium from its group?
As an f-block element Uranium is not assigned a group; examiners accept its common valency of 4 and 6.
Why does Uranium show variable valency?
Because both its outer shell and the nearby inner subshell can participate in bonding, Uranium forms more than one stable ion — hence valencies 4 and 6.