section_heading: Povijest
paragraph_text: <table cellspacing="5"> <tr> <th align="center" colspan="3">Neke trijade</th> </tr><tr> <th>Element</th> <th>Atomska masa</th> <th>Gustoća</th> </tr><tr> <td>klor</td> <td>35.5</td> <td>0.00156 g/cm<sup>3</sup></td> </tr><tr> <td>brom</td> <td>79.9</td> <td>0.00312 g/cm<sup>3</sup></td> </tr><tr> <td>jod</td> <td>126.9</td> <td>0.00495 g/cm<sup>3</sup></td> </tr> <tr><td>&nbsp;</td></tr><tr> <td>kalcij</td> <td>40.1</td> <td>1.55 g/cm<sup>3</sup></td> </tr><tr> <td>stroncij</td> <td>87.6</td> <td>2.6 g/cm<sup>3</sup></td> </tr><tr> <td>barij</td> <td>137</td> <td>3.5 g/cm<sup>3</sup></td> </tr> </table>