How Mendeleev’s Dream Helped Him Invent the Periodic Table
<p>The dream showed him a pattern that he had not noticed before: when the elements were ordered by increasing atomic weight, their properties repeated periodically. He realized that this was a natural law that governed the behavior of the elements. He also <em>left</em> some gaps in his table, predicting that new elements would be discovered to fill them. He even predicted some of their properties based on the patterns he observed.</p>
<p><img alt="" src="https://miro.medium.com/v2/resize:fit:700/1*In8DoIdQk1XmUUM-n8ao5w.jpeg" style="height:1011px; width:700px" /></p>
<p>Handwritten manuscript of the arrangement of elements written by Mendeleev, ca. 1869. Public domain image. <a href="https://commons.wikimedia.org/wiki/File:Mendeleev_law.jpg" rel="noopener ugc nofollow" target="_blank">Wikimedia Commons</a>.</p>
<p>Mendeleev’s dream was not a random occurrence, but a result of his subconscious mind working on the problem that he had been trying to solve for a long time. His dream was based on his previous knowledge and observations of the elements, but it also revealed something new and unexpected.</p>
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