The goal is for the output to resemble something like the following where you have a '1' on the top and on the bottom it refers to the '1' providing more information.
Now, my values in the table are different, but it should still resemble that image.
\begin{table}[!ht]
\centering
\caption{Atomic Numbers and Melting Points in Kelvin of Elements O, S, Se, Te, and Po.\label{table:elements}}
\begin{tblr}{
colspec={|c|c|c|},
row{1} = {font=\bfseries, bg=black!15}
}
\toprule
Element & Atomic Number & Melting Point (K) \\
\midrule
Oxygen & 8 & 54.8 \\
Sulfur & 16 & 388.36 \\
Selenium & 34 & 494 \\
Tellurium & 52 & 722.66 \\
Polonium & 84 & 528 \\
\bottomrule
\end{tblr}
\end{table}
I am sure that there is a better way, but this is what I did.
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[export]{adjustbox}
\usepackage{graphicx}
\graphicspath{ {./figures/} }
\usepackage[labelfont=bf]{caption}
\usepackage[most]{tcolorbox}
\usepackage{tabularray}
\usepackage{hyperref}
\usepackage{ulem}
\hypersetup{
colorlinks=true, % false: boxed links; true: colored links
urlcolor=blue % color of external links
}
\UseTblrLibrary{booktabs}
\pagenumbering{gobble}
\begin{document}
\begin{table}[!ht]
\centering
\caption{Atomic Numbers and Melting Points in Kelvin of Elements O, S, Se, Te, and Po.\textsuperscript{1}}
\begin{tblr}{
colspec={|c|c|c|},
row{1} = {font=\bfseries, bg=black!15}
}
\toprule
Element & Atomic Number & Melting Point (K) \\
\midrule
Oxygen & 8 & 54.8 \\
Sulfur & 16 & 388.36 \\
Selenium & 34 & 494 \\
Tellurium & 52 & 722.66 \\
Polonium & 84 & 528 \\
\bottomrule
\end{tblr}
\end{table}
\footnotesize{\textsuperscript{1}Periodic Table, \color{blue}\uline{\url{https://ptable.com/\#Properties}} \color{black}(accessed September 12, 2022)}
\end{document}