1. How did Mosely contribute to the periodic table arrangement? 2. What information did Mosley have about atomic structure that Mandeleev did not have?

1. Mosely arranged the elements based on the increasing number of protons, atomic number.

2. According to Moseley, similar properties recur periodically when elements are arranged according to increasing atomic number. Atomic numbers, not weights, determine the factor of chemical properties. Mendeleev ordered his elements in order of their relative atomic mass, and this gave him some problems.

Explanation:

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