Alkaline earth metals belong to Group 2 of the periodic table and have the general electronic configuration of [noble gas] ns, where 'n' represents the period number. These metals include Beryllium Be , Magnesium Mg , Calcium Ca , Strontium Sr , Barium Ba , and Radium Ra . As we move down the group, the reactivity of alkaline earth metals increases. This is because the atomic size increases, leading to a decrease in ionization energy, which makes it easier for the metals to lose their two valence electrons and form a +2 ion.Halogens belong to Group 17 of the periodic table and have the general electronic configuration of [noble gas] ns np, where 'n' represents the period number. These elements include Fluorine F , Chlorine Cl , Bromine Br , Iodine I , and Astatine At . As we move down the group, the reactivity of halogens decreases. This is because the atomic size increases, leading to a decrease in electronegativity and electron affinity, which makes it harder for the halogens to gain an electron and form a -1 ion.When alkaline earth metals react with halogens, they form metal halides. The reactivity trend can be predicted based on the trends mentioned above. Highly reactive alkaline earth metals will readily react with highly reactive halogens. For example, Barium Ba , a highly reactive alkaline earth metal, will react vigorously with Fluorine F , a highly reactive halogen, to form Barium fluoride BaF .In summary, the reactivity trend of alkaline earth metals increases as we move down the group, while the reactivity trend of halogens decreases as we move down the group. The reactivity between these two groups can be predicted based on these trends, with more reactive elements forming compounds more readily.