Final answer:
The reactivity of alkaline earth metals increases down the group due to decreased ionization energy, which causes the ease of oxidation and the facility to lose valence electrons. The increase in atomic radius decreases the hold of the nucleus on the valence electrons, thus enhancing reactivity despite the higher ionization energy compared to the alkali metals.
Step-by-step explanation:
The reactivity of alkaline earth metals increases as you move down the group in the periodic table primarily due to the decrease in ionization energy. This means that atoms lower in the group tend to lose their valence electrons more easily, facilitating reactions. A key aspect is the atomic radius, which increases as you go down a group, placing the outermost electrons farther from the positive attraction of the nucleus. Consequently, these electrons are less tightly held and more readily involved in chemical reactions. Alkaline earth metals, like their neighbors the alkali metals, are known for their reactivity. Although both are reactive, the alkaline earth metals exhibit a higher ionization energy compared to alkali metals, which is attributed to the increase in nuclear charge from group 1 to group 2.
As the atomic number increases, so does the ease of oxidation, hence the reactivity of these metals increases down the group. The alkaline earth metals are quite reactive, readily losing both valence electrons to form +2 oxidation state compounds. However, their reactivity, while high, is somewhat mitigated compared to group 1 metals due to the appearance of a pseudo-noble gas configuration upon ion formation. Despite this, the general trend remains the same for both group 1 and group 2 metals: reactivity increases with the increasing atomic number within these groups.