LaTeX fun with periodic tables

For a while now I've wanted to generate a simple periodic table of elements in LaTeX. I've googled around a bit without too much joy. So I've made a simple one myself.

Here is the code:

\documentclass[a4paper,12pt]{article}
\pagestyle{empty}

\usepackage{rotating}

\linespread{1.2}

\begin{document}

\begin{sidewaystable}

 {

  \renewcommand{\arraystretch}{1.5}

  \bfseries

\centering

\begin{tabular}{|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|c|}

\cline{1-1} \cline{18-18}

H &       \multicolumn{16}{|c|}{}                                                  & He \\

\cline{1-2} \cline{13-18}

Li & Be & \multicolumn{10}{|c|}{}                         & Bo & C  & N  & O  & Fl & Ne \\

\cline{1-2} \cline{13-18}

Na & Mg & \multicolumn{10}{|c|}{}                         & Al & Si & P  & S  & Cl & Ar \\

\hline

K  & Ca & Sc & Ti & V  & Cr & Mn & Fe & Co & Ni & Cu & Zn & Ga & Ge & As & Se & Br & Kr \\

\hline

Rb & Sr & Y  & Zr & Nb & Mo & Tc & Ru & Rh & Pd & Ag & Cd & In & Sn & Sb & Te & I  & Xe \\

\hline

Cs & Ba & *  & Hf & Ta & W  & Re & Os & Ir & Pt & Au & Hg & Tl & Pb & Bi & Po & At & Rn \\

\hline

Fr & Ra & ** & Rf & Db & Sg & Bh & Hs & Mt & Ds & Rg & Cn & Uut & Uuq & Uup & Uuh & Uus & Uuo \\

\hline

\end{tabular}

}

\end{sidewaystable}

\end{document}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

And here is the resulting table: