$ \mathrm{Sr}^{2+}(\mathrm{Z}=38), \mathrm{Cs}^{+}(\mathrm{Z}=55), \mathrm{La}^{2+}(\mathrm{Z}=57) \mathrm{Pb}^{2+} $
$ (\mathrm{Z}=82), \mathrm{Yb}^{2+}(\mathrm{Z}=70) \text { and } \mathrm{Fe}^{2+}(\mathrm{Z}=26)$
(નજીકનાં પૂર્ણાંકમાં રાઉન્ડ ઑફ કરો) $\left[ h =6.63 \times 10^{-34}\, Js , c =3.00 \times 10^{8} \,ms ^{-1}\right.$ $,$ $\left. N _{ A }=6.02 \times 10^{23}\, mol ^{-1}\right]$