How did Dmitri Mendeleev arrange the elements in his original periodic table?

• A. By alphabetical order
• B. By increasing atomic mass
• C. By increasing atomic number
• D. By decreasing atomic radius

Answer: (B)

Verified step by step guidance

1. Understand that Dmitri Mendeleev's original periodic table was an early attempt to organize elements based on their properties and atomic characteristics.
2. Recall that Mendeleev arranged the elements primarily by increasing atomic mass, which was the best available measure at the time to reflect periodic trends.
3. Recognize that Mendeleev noticed patterns in element properties recurring periodically when elements were listed in order of increasing atomic mass.
4. Note that Mendeleev left gaps in his table for elements that were not yet discovered, predicting their properties based on the trends he observed.
5. Understand that the modern periodic table arranges elements by increasing atomic number, but Mendeleev's original method was based on atomic mass.