Oh yes, how about the arrangement of these eighteen "absolutely identical" elements in the Periodic System? To be honest, we are not very clear on this point ourselves. The more so, that there is still much controversy concerning the situation of the lanthanides and actinides, though this question is far more simple.

   We wish you all a long life. But we do not think there will be any of our readers alive by the time the location of the eighteen elements in the Big House becomes a question of practical interest. But our readers' descendants, near or remote, will surely have to solve this problem. 

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