Respuesta :
because they're just meant to be arranged by atomic mass--it's just how the scientists of the late 1860s wanted it to be ordered
The periodic table is the arrangement of the elements in the periods and groups. They are not in order as they are arranged based on their atomic numbers.
What are the periodic table and atomic numbers?
The periodic table is the classification of the elements like alkali metals, alkaline, transitions metals, noble gases, metalloids, lanthanides etc. based on the increasing atomic numbers.
The atomic number of the elements is the number of protons present in the nucleus of the elemental atom. The atomic number defines the chemical and physical properties of the element.
Therefore, elements are not in the increasing order of the atomic mass as they are arranged based on the atomic number.
Learn more about the periodic table and atomic numbers here:
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