Answer:
The correct answer is A.
Explanation:
The periodic table published by Mendeleev in 1869 was the first periodic table to group the elements. Based on the hypothesis that the properties of the elements are a periodic function of their atomic weights, he placed in the table all the elements known up to that moment, which became 63 elements, ordering them in such a way that the elements belonging to the same family appear in the same vertical line. The elements were arranged in the increasing order of their atomic masses.
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