Write the electron configuration for ni2+. use the buttons at the top of the tool to add orbitals in order of orbital filling, starting at the bottom with the lowest-energy orbitals. click within an orbital to add electrons. g.com

The atomic number of Nickle is 28, so its electronic configuration in ground state is,

Ni  =  28 e⁻  =  1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d⁸

So, when Nickle looses two electrons it will attain +2 charge, remaining with 26 electrons as,

Ni⁺²  =  26 e⁻  =  1s², 2s², 2p⁶, 3s², 3p⁶, 3d⁸

Ni looses electrons from 4s shell instead instead of 3d shell because the 4s shell electrons are at larger distance as compared to 3d, hence, felting less nuclear charge and easily lost.

A salad is a mixture but h2o is a mixture of molechules