IMAT Chemistry Practice Exam

Group 1 alkali metals are highly reactive with water, and their reaction produces basic solutions. They have one valence electron, so they readily lose it to form M+ ions. When they react with water, hydroxide ions are formed along with hydrogen gas: 2 M + 2 H2O → 2 M+ + 2 OH− + H2. The hydroxide ions make the solution alkaline (very basic). This behavior is a defining property of alkali metals. They are not noble gases (which are inert), they do not have 2 valence electrons, and they do not form 2+ cations—they form +1 cations. Hence, forming alkaline solutions on reaction with water is the correct description.