($Zn =30,\,Ni =28$ અને $Cr =24$ના પરમાણ્વીય ક્રમાંક )
In this case \(Zn ^{2+}\) have total \(28\) numbers of electrons. \(Cr ^{3+}\) have total \(21\) numbers of electrons and \(Ni ^{2+}\) have total \(26\) numbers of electrons.
(પ. ક્ર. $Ce = 58,\,Lu = 71,\,La = 57,\,Yb = 70$ )