In a different experiment, a student places a piece of pure ba(s) in a beaker containing 250. Ml of 6. 44mhcl(aq) and observes that the rate of appearance of h2(g) bubbles when ba(s) was added is much faster than the rate of appearance of bubbles when the mg(s) was added. The student claims that the greater reactivity is due to the difference in ionization energy between mg and ba. Explain the difference in ionization energy between mg and ba in terms of atomic structure.