Final answer:
The statement is true; alkali metals other than lithium typically react with oxygen to form metal peroxides containing the (O₂²⁻) ion. The stability of these compounds increases with the size of the alkali metal cation, with larger cations forming more stable peroxides and superoxides.
Step-by-step explanation:
The statement that alkali metals other than lithium react with oxygen to form metal peroxides containing the (O₂²⁻) ion is true. While lithium reacts to form mainly lithium oxide (Li₂O), the other alkali metals such as sodium, potassium, rubidium, and cesium typically form peroxides (M₂O₂) or superoxides (MO₂) when they react with oxygen. The formation of these compounds depends on the reaction conditions and the size of the metal cation, with larger cations (found in metals towards the bottom of the group) tending to form superoxides, whereas smaller cations (found in metals towards the top of the group, like lithium) usually form oxides.
The stability of peroxides and superoxides increases as we move down the group in the periodic table because larger cations stabilize the larger peroxide and superoxide anions. Compounds with smaller cations, such as lithium, prefer to form simpler oxides. The formation of various oxides, peroxides, and superoxides by alkali metals illustrates the diversity of their chemistry and their reactivity with oxygen.