Final answer:
NO2, nitrogen dioxide, is not an example of an ionic bond since it's formed from two nonmetals that share electrons (covalent bond), whereas MgI2, magnesium iodide, is an ionic compound with metals and nonmetals forming ions.
Step-by-step explanation:
Among the choices given, NO2, nitrogen dioxide, is NOT an example of an ionic bond. Ionic bonds occur between metals and nonmetals where electrons are transferred from the metal to the nonmetal, creating ions with opposite charges that attract each other. Nitrogen dioxide, however, consists of nitrogen and oxygen, both of which are nonmetals. Therefore, NO2 molecules are held together by covalent bonds, where electrons are shared between nonmetal atoms to achieve stability.
In contrast, MgI2, magnesium iodide, is an ionic compound. Magnesium, being a metal, loses electrons to form Mg2+ ions, while iodine, a nonmetal, gains electrons to form I- ions. The resultant oppositely charged ions strongly attract each other, forming an ionic bond and resulting in a crystalline solid.