Within the same period, why are alkaline earth metals (group 2) less reactive than alkali metals (group 1)?

1. Reactivity of a metal is closely tied to how easily it gives up its valence electrons -- a lower ionization energy generally means higher reactivity. 2. The text explains: "the atoms of the alkaline earth metals are smaller and have higher first ionization energies than the alkali metals within the same period. The higher ionization energy makes the alkaline earth metals less reactive than the alkali metals." 3. Alkaline earth metals do form cations (with a 2+ charge) and clearly have valence electrons (two of them), so those options are factually wrong. 4. So the smaller size and higher ionization energy of alkaline earth metals, compared to alkali metals in the same period, explain their lower reactivity. _Source: OpenStax Chemistry Ch 18 "Representative Metals, Metalloids, and Nonmetals", p.970 §18.1 Periodicity_