\documentclass[10pt,a4paper]{extarticle}

% Package imports
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{chemfig}
\usepackage[version=4]{mhchem}
\usepackage{graphicx}
\usepackage{geometry}
\usepackage{hyperref}
\usepackage{booktabs}
\usepackage{longtable}
\usepackage{array}
\usepackage{float}

% Page layout
\geometry{
    margin=1in
}

% Document information
\title{Chemistry Vocabulary}
\author{}
\date{}

\setlength{\parindent}{0pt}

\begin{document}

\maketitle

\section*{Introduction}

\input{contents/elements.tex}
\input{contents/ions.tex}
\input{contents/ore.tex}
\input{contents/reactions.tex}
\input{contents/nomenclature.tex}
\input{contents/organic.tex}

\input{contents/macromolecule.tex}

\end{document}