How many unpaired electrons are present in \(Ni^{2+}\)?

2

The correct answer is option 3. 2.

Nickel has an atomic number of 28.

The electronic configuration of \(Ni\) is \([_{18}Ar]4s^2 3d^8\)

When nickel forms a \(Ni^{2+}\) ion, it loses 2 electrons, leaving it with 26 electrons to form \(Ni^{2+}\) it loses its electrons from the \(4s\)-subshell and the configuration changes to:

It has 2 unpaired electrons.