Which of the following has maximum number of unpaired d-electrons Zn,Fe+2,Ni+3,Cu+

To determine which of the following elements has the maximum number of unpaired d-electrons, we need to examine their electron configurations.

1. Zn (Zinc): The atomic number of zinc is 30. Its electron configuration is [Ar] 3d10 4s2. Since all the d-electrons are paired, Zn has zero unpaired d-electrons.

2. Fe+2 (Iron ion): The atomic number of iron is 26. When it loses two electrons to form Fe+2, its electron configuration becomes [Ar] 3d6. Therefore, Fe+2 has four unpaired d-electrons.

3. Ni+3 (Nickel ion): The atomic number of nickel is 28. When it loses three electrons to form Ni+3, its electron configuration becomes [Ar] 3d7. Hence, Ni+3 has three unpaired d-electrons.

4. Cu+ (Copper ion): The atomic number of copper is 29. When it loses one electron to form Cu+, its electron configuration becomes [Ar] 3d10. Therefore, Cu+ has zero unpaired d-electrons.

Comparing the four elements, we find that Fe+2 has the maximum number of unpaired d-electrons, which is four.