\[
\begin{array}{|c|c|}
\hline \multicolumn{2}{|c|}{\text{two polyatomic anions}} \\
\hline \text{name} & \text{chemical formula} \\
\hline \text{nitrite anion} & \boxed{\mathrm{NO}_2^-} \\
\hline \text{sulfate anion} & \boxed{\mathrm{SO}_4^{2-}} \\
\hline
\end{array}
\]