Valency of Ytterbium (Yb)
Ytterbium shows variable valency — most commonly 2 and 3 — because it is a f-block element whose outer electrons can join bonding in more than one way.
This is the fast lane: one page, one fact, zero digressions. Read the quick answer, check the table, and if your exam needs the full derivation, the sections below walk through it step by step — in Bangla and English, like every page here. Need the whole picture instead — history, characteristics, uses, exam questions? The full Ytterbium page is one click away.
Counting the valence electrons
From the configuration [Xe] 4f^14 6s^2, Ytterbium'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: Ytterbium belongs to the f-block of the periodic table, period 6.
Why Ytterbium 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 Ytterbium can offer different numbers of them in different compounds — giving ions such as Yb²⁺ and Yb³⁺ and families of compounds like YbX / Yb₃X₂.
Valency vs valence electrons
Valence electrons are what you count (2 for Ytterbium); 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 Ytterbium from its group?
As an f-block element Ytterbium is not assigned a group; examiners accept its common valency of 2 and 3.
Why does Ytterbium show variable valency?
Because both its outer shell and the nearby inner subshell can participate in bonding, Ytterbium forms more than one stable ion — hence valencies 2 and 3.