The previous sections of this chapter presented, compared, and contrasted the definitions of Arrhenius, Brønsted-Lowry, and Lewis acids and bases. Arrhenius acids and bases produce hydrogen ions, H+1, and hydroxide ions, OH–1, respectively, when dissolved in water. Because these ions are analyzed as independent chemical entities, the Arrhenius system for classifying acids and bases is inherently less sophisticated than both the Brønsted-Lowry and Lewis systems, in which acids and bases are defined by synergistic proton-transfer and electron-transfer relationships, respectively. Consequently, the reactivity of Arrhenius acids and bases is limited, but predictable. However, in order to recognize Arrhenius reactants and, subsequently, predict the products that are generated when these substances participate in chemical reactions, chemical formula patterns for writing or identifying the formulas of Arrhenius acids and bases must first be developed and applied. Therefore, the following sections of this chapter will present three patterns that can be used to write or recognize the chemical formulas of and, subsequently, name, Arrhenius acids and Arrhenius bases.