\documentclass{article}
\usepackage{tabularx}
\usepackage{booktabs}
\usepackage[version=4]{mhchem}
\usepackage{array}
\begin{document}
\begin{tabularx}{1\linewidth}{*{7}{>{\centering\arraybackslash}X}}
\toprule
\(n\) & 1 & 2 & 3 & 4 & 5 & 6\\
\midrule
\ce{Na^+} & 3 & 4 & 5 & 6 & 6 & 7\\
\ce{K^+} & 2 & 4 & 5 & 7 & 7.2 & 8\\
\ce{Ca^2+} & 9 & 10 & 10.5 & 11.2 & 11.5 & 11.9\\
\bottomrule
\end{tabularx}
\end{document}
问 请教一下这里面的内容怎么设置成等宽?