Ionisation Energies Fall In Group 2
As you go down one in group 2, an entire extra shell is being added, this does make it more reactive as there is even less of a nuclear attraction for every sub shell you move into.
Ionisation Energies Increase Across A Period
Ionisation energies across a period tend to increase (harder to remove outer electron). This is due to number of protons increasing meaning a stronger nuclear attraction. All of the outer electrons are on roughly the same energy level anyway, and there is generally less extra shielding due to the close…