When alkali metals react with water, they produce hydrogen gas and a hydroxide. What is the primary reason for the high reactivity of alkali metals with water?

Alkali metals have a single electron in their outer shell, making that electron very easy to give up; their ionization energy is very low. When they touch water, that loose electron is quickly transferred to a water molecule, breaking the O–H bonds and creating hydrogen gas and a hydroxide ion. The resulting Na⁺ (or K⁺) ion strongly attracts the hydroxide, forming a stable ionic pair that pulls the reaction forward. Because this electron transfer is so energetically favorable, alkali metals react vigorously with water, as seen when sodium reacts to produce NaOH and H₂. The key idea is that the low ionization energy and high electropositivity of alkali metals drive this rapid, exothermic reaction.