Chemistry - Chemical Kinetics Question with Solution | TestHub

As metal ion${\mathrm{M}}^{2+}$has an electron configuration of 2, 8, 14 so
The metallic atom (M) has a total number of electron$=2+8+14+2=26$.
Therefore, the number of protons in the nucleus = 26.
Hence, the number of neutrons$=\mathrm{A}-\mathrm{Z}=56-26=30$.