When I use this code: \toprule works well. \bottomrule appear on the bottom but this error occurs: misplaced \noalign \bottomrule. You know why? Thank you!
\begin{quadro}
\caption{Experiência com ensino de italiano - grupos 1 e 2}
\label{quad:experiencia_com_ensino_de_italiano_grupos1_e2}
\begin{tabular}{c}
\toprule
\begin{minipage}{.5\textwidth}
\renewcommand{\bcfontstyle}{} %muda a fonte do gráfico - bchart - para o padrão do documento.
\begin{bchart}[step=50, max=100, unit=\%, scale=0.4]
\bcxlabel{Grupo 1}
\bcbar[label=Sim]{76}
\medskip
\bcbar[label=Não]{24}
\end{bchart}
\end{minipage}
\begin{minipage}{.5\textwidth}
\renewcommand{\bcfontstyle}{} %muda a fonte do gráfico - bchart - para o padrão do documento.
\begin{bchart}[step=50,max=100, unit=\%, scale=0.4]
\bcxlabel{Grupo2}
\bcbar[label=Sim]{91}
\medskip
\bcbar[label=Não]{9}
\end{bchart}
\end{minipage}
\bottomrule
\end{tabular}
\end{quadro}
\\
before the rule, your table will be too wide, the content of the c column is two minipages .5\textwidth wide separated by an inter-word-space, and then you have\tabcolsep
space either side from the table padding so the total is 2\tabcolsep+ 1space wider than the page.