Who arranged the 56 elements in an ascending order of their atomic mass and found that each 8th element had the same properties?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. John Newlands .
John Newlands, an English chemist, proposed the Law of Octaves in 1865. He arranged the 56 known elements of his time in order of increasing atomic mass and observed that every eighth element shared similar chemical properties, much like musical notes repeating every eighth note in an octave. This was one of the earliest attempts to classify elements based on patterns in their properties. Although his idea was initially criticized and not widely accepted, it was later recognized as an important step toward the development of the modern periodic table. Newlands' work helped highlight periodic trends in elements.