<div class="line"><a name="l00009"></a><span class="lineno">    9</span>&#160;                                               <span class="stringliteral">&#39;F&#39;</span>, <span class="stringliteral">&#39;CL&#39;</span>, <span class="stringliteral">&#39;BR&#39;</span>, <span class="stringliteral">&#39;I&#39;</span>,  <span class="comment">#halogens</span></div><div class="line"><a name="l00010"></a><span class="lineno">   10</span>&#160;                                               <span class="stringlite