Comparing the Concentration of Some Alkalis in Saturated Solutions

When metals from groups one and two of the periodic table combine with an OH molecule, the type of intramolecular bonding is ionic bonding. The metals lose one or more electrons and so become positively charged. The non-metal ions/ molecules gain electrons and so become negatively charged. The oppositely charged ions attract each other to form a rigid 3-D lattice a. Each ion in the lattice is surrounded by others of opposite charge e.g. NaOH:Due to their polar nature, ionic compounds are usually soluble in polar solvents, for example water:Water is polar due the difference in electronegativity between the oxygen and hydrogen atoms.This is represented by ?+ and ?-.When this amount is reached, it gives a saturated solution c. In a saturated solution, e.g. Ca(OH)2 (aq), Ca2+ and OH- ions are in equilibrium with the solid calcium hydroxide:Ca(OH)2 (aq) Ca2+ + 2OH-The solubility of group one and two hydroxides varies greatly, however, clear trends can be seen:Metal HydroxideMr (g)Moles sat (mol/100g)LiOH023.95.16×10-1NaOH040.01.05KOH056.11.71RbOH102.51.69(303K)CsOH150.02.02(303K)