Pre-Mendeleyev, many chemists and scientists already sought out to carve a system or some method of organizing the known elements in a logical way. Many tried but came short since they didn't have all the information regarding the elements. However, it was quite clear to some that patterns existed in the properties of the elements.
From the law of triads to the law of octaves, chemistry had to sojourn for quite some time before the elements could all be consolidated together in the modern periodic table. In large part, this history of the periodic table is obscure to most, at least to my knowledge.
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