## Chemistry (4th Edition)

(a) oxygen (O$_{2}$) and nitrogen (N$_{2}$) (b) water (H$_{2}$O) and table salt (NaCl) (c) ozone (O$_{3}$) and octasulfur (S$_{8}$) (d) sodium bicarbonate (NaHCO$_{3}$) and magnesium hydroxide (Mg(OH)$_{2}$)
(a) Diatomic means the molecule has two atoms bonded together. This question is asking for diatomic molecules with atoms of the same element. Two examples are O$_{2}$ and N$_{2}$, which occur naturally. (b) Diatomic molecules consisting of different elements are basically binary compounds, compounds consisting of two elements. Two examples are water (H$_{2}$O) and table salt (NaCl). (c) A polyatomic molecules with atoms of the same element means three or more molecules of the same element bonded together. Two examples are ozone (O$_{3}$) and octasulfur (S$_{8}$). (d) A polyatomic molecule consists of three or more elements chemically bonded together. Two examples are sodium bicarbonate (NaHCO$_{3}$) and magnesium hydroxide (Mg(OH)$_{2}$).