Which chemist was the first to organize the elements in order of increasing atomic number?

• A. Antoine Lavoisier
• B. John Dalton
• C. Henry Moseley
• D. Dmitri Mendeleev

Answer: (C)

Verified step by step guidance

1. Understand that the question is about the historical development of the periodic table and the organization of elements.
2. Recall that Antoine Lavoisier and John Dalton contributed to early chemistry and atomic theory but did not organize elements by atomic number.
3. Recognize that Dmitri Mendeleev created the first widely recognized periodic table, organizing elements by increasing atomic mass, not atomic number.
4. Identify Henry Moseley as the chemist who used X-ray spectra to determine atomic numbers and reorganized the periodic table based on increasing atomic number.
5. Conclude that Henry Moseley was the first to organize elements in order of increasing atomic number, which corrected inconsistencies in Mendeleev's table.