Nickel atom can lose two electrons to form `Ni^(2+)` ion. The atomic number of nickel is 28. From which orbital will nickel lose two electrons?

Explanation

`._(28)N=1s^(2),2s^(2),2p^(6),3s^(2),3p^(6),3d^(6),4s^(2)`. Nickel will lose 2 electorns from 4s (outermost shell) to form `Ni^(2+)` ion.
Hence `._(26)Ni^(2+)=1s^(2),2s^(2),2p^(6) ,3s^(2),3p^(6),3d^(8),4s^(0)`.