How was the work of Newlands similar to that of Mendeleev on the periodic table?

• A. Both left gaps for undiscovered elements based on predicted properties.
• B. Both classified elements into noble gases and transition metals.
• C. Both used atomic number as the basis for arrangement.
• D. Both arranged elements in order of increasing atomic mass.

Answer: (D)

Verified step by step guidance

1. Understand the historical context: Both Newlands and Mendeleev worked in the 19th century to organize elements into a periodic system before the discovery of atomic number.
2. Recognize Newlands' contribution: He proposed the Law of Octaves, arranging elements in order of increasing atomic mass and noticing repeating properties every eighth element.
3. Recognize Mendeleev's contribution: He arranged elements by increasing atomic mass but also left gaps for undiscovered elements, predicting their properties based on trends.
4. Compare their approaches: Both scientists arranged elements primarily by increasing atomic mass, which was the best available property at the time for ordering elements.
5. Note the difference from modern periodic table: Unlike the modern table, neither used atomic number as the basis for arrangement, and noble gases were not classified by Newlands since they were discovered later.