Question

Which of the following transition metals shows +1 and +2 oxidation states ?

• A. Mn
• B. Zn
• C. Cu
• D. Sc

Hint:

Copper (3d⁸4s¹) can lose one electron (Cu⁺) or two (Cu²⁺).

Answer 1

The Correct Option is C

Concept: The oxidation states a metal can show come from how many electrons it is able to lose from its outer 4s and 3d sub-shells. So we look for the metal that can lose either one electron or two.

Step 1: Look at copper
Copper has the arrangement $\mathrm{[Ar]3d^{10}4s^1}$. If it loses just the one 4s electron, it becomes $\mathrm{Cu^+}$, that is $+1$. If it then loses one more electron from the 3d shell, it becomes $\mathrm{Cu^{2+}}$, that is $+2$. So copper naturally shows both states.

Step 2: Check the others
Scandium $\mathrm{(3d^1 4s^2)}$ loses all three outer electrons and shows only $+3$. Zinc $\mathrm{(3d^{10}4s^2)}$ loses two and shows only $+2$. Manganese shows many states from $+2$ to $+7$, but $+1$ is not a normal one for it.

Step 3: Conclude
Only copper clearly shows both $+1$ and $+2$.

Answer: Option (C), Cu (it forms $\mathrm{Cu^+}$ and $\mathrm{Cu^{2+}}$).