Final answer:
The alkalinity of the solutions formed from Group 2 oxides and water increases down the group, due to the larger atomic size and lower ionization energy, which facilitate the formation of hydroxides.
Step-by-step explanation:
The trend in alkalinity of the solutions formed when Group 2 oxides are added to water increases down the group. This is because the heavier alkaline earth metals have oxides that react with water to produce more alkaline solutions.
As we move down the group from beryllium to radium, the atomic size increases, and the ionization energy decreases, making it easier for these metals to lose their two valence electrons and form hydroxides with water. These hydroxides are basic due to the presence of hydroxide ions (OH-), which increase the pH of the solution.