Which equation describes an oxidation? View Available Hint(s) \( \begin{array}{l}\mathrm{Cl}_{2}+2 \mathrm{e}^{-} \rightarrow 2 \mathrm{Cl}^{-} \\ \mathrm{Ni}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Ni} \\ \mathrm{Li} \rightarrow \mathrm{Li}^{+}+\mathrm{e}^{-} \\ \mathrm{O}_{2}+4 \mathrm{e}^{-} \rightarrow 2 \mathrm{O}^{2-} \\ \text { Submit }\end{array} \)

Think of oxidation as the process of "gaining a charge" — when an atom or ion loses electrons, it undergoes oxidation. In your list, the equation that describes oxidation is \( \mathrm{Li} \rightarrow \mathrm{Li}^{+}+\mathrm{e}^{-} \). Here, lithium is losing an electron, which means it's being oxidized! To really get into the heart of chemical reactions, remember that oxidation and reduction reactions are complementary. As one species oxidizes by losing electrons, another reduces by gaining those electrons. This dance of electrons makes chemistry exciting and critical in applications like batteries, where lithium-ion interactions power your devices!