Look at the position of Pb in the periodic table and the postion of the Alkali Earth metals. Alkali Earth Metals are in noble-gas configuration when they are doubly charged cations. Lead however is on the right hand side, and would like to have more electrons to get into that stablest configuration; making the bonds in lead-compounds more covalent -and stronger- in nature. Insoluble compounds have lattice enthalpies higher than the enthalpy of solvation. Now since Alkali Earth metals like to be in ionic states; their compounds will dissolve in general more easily than the same compounds with lead, since usually the lattice energy of lead compounds is much higher (In case of insoluble compounds higher than the energy that would be released upon solvation, which thus doesn\'t occur). Solution Look at the position of Pb in the periodic table and the postion of the Alkali Earth metals. Alkali Earth Metals are in noble-gas configuration when they are doubly charged cations. Lead however is on the right hand side, and would like to have more electrons to get into that stablest configuration; making the bonds in lead-compounds more covalent -and stronger- in nature. Insoluble compounds have lattice enthalpies higher than the enthalpy of solvation. Now since Alkali Earth metals like to be in ionic states; their compounds will dissolve in general more easily than the same compounds with lead, since usually the lattice energy of lead compounds is much higher (In case of insoluble compounds higher than the energy that would be released upon solvation, which thus doesn\'t occur)..

1. Look at the position of Pb in the periodic table and the postion of the Alkali Earth
metals. Alkali Earth Metals are in noble-gas configuration when they are doubly charged
cations. Lead however is on the right hand side, and would like to have more electrons to get into
that stablest configuration; making the bonds in lead-compounds more covalent -and stronger- in
nature. Insoluble compounds have lattice enthalpies higher than the enthalpy of solvation. Now
since Alkali Earth metals like to be in ionic states; their compounds will dissolve in general more
easily than the same compounds with lead, since usually the lattice energy of lead compounds is
much higher (In case of insoluble compounds higher than the energy that would be released upon
solvation, which thus doesn't occur).
Solution
Look at the position of Pb in the periodic table and the postion of the Alkali Earth
metals. Alkali Earth Metals are in noble-gas configuration when they are doubly charged
cations. Lead however is on the right hand side, and would like to have more electrons to get into
that stablest configuration; making the bonds in lead-compounds more covalent -and stronger- in
nature. Insoluble compounds have lattice enthalpies higher than the enthalpy of solvation. Now
since Alkali Earth metals like to be in ionic states; their compounds will dissolve in general more
easily than the same compounds with lead, since usually the lattice energy of lead compounds is
much higher (In case of insoluble compounds higher than the energy that would be released upon
solvation, which thus doesn't occur).