The metals have a tendency to lose electrons and convert into positive ions which go into solution when placed in water. The redox potentials depend on (i) Sublimation energy of the solid metal, (ii) Ionization energy of gaseous metals atom (iii) Hydration energy of gaseous atom. Electrode Potentials $(E°)$  can be calculated using  $\Delta G°=\Delta H°-T\Delta S°=-nFE°.$ Neglecting entropy charge $\Delta G°=\Delta H°=-nFE°.\Delta H°$  is the $\Delta H$ reaction i.e, for redox reaction between metal and hydrogen since the electrode potentials are measured with reference to hydrogen.