Valency of Nickel (Ni)
Nickel 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.
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 Nickel page is one click away.
Counting the valence electrons
From the configuration [Ar] 3d^8 4s^2, Nickel'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: Nickel belongs to group 10 of the periodic table, period 4.
Why Nickel 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 Nickel can offer different numbers of them in different compounds — giving ions such as Ni²⁺ and Ni³⁺ and families of compounds like NiX / Ni₃X₂.
Valency vs valence electrons
Valence electrons are what you count (2 for Nickel); 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 Nickel from its group?
Nickel sits in group 10; for this transition group the safe exam answer is its common valency, 2 and 3.
Why does Nickel show variable valency?
Because both its outer shell and the nearby inner subshell can participate in bonding, Nickel forms more than one stable ion — hence valencies 2 and 3.