Why did Dmitri Mendeleev organize the elements into a periodic table?

• A. To separate metals from nonmetals using alphabetical order
• B. To arrange elements by increasing atomic mass and reveal repeating chemical properties
• C. To classify elements based on their color and physical state
• D. To group elements according to their electrical conductivity

Answer: (B)

Verified step by step guidance

1. Understand the historical context: Dmitri Mendeleev was trying to find a way to organize the known chemical elements to better understand their properties and relationships.
2. Recognize that Mendeleev arranged elements in order of increasing atomic mass, which was the best available measure at the time to distinguish elements.
3. Observe that by arranging elements by increasing atomic mass, Mendeleev noticed a pattern of repeating chemical properties at regular intervals, which he called the periodicity of elements.
4. This periodicity allowed Mendeleev to group elements with similar chemical behaviors into columns (groups or families) in the table, predicting properties of undiscovered elements.
5. Therefore, the main purpose of Mendeleev's periodic table was to organize elements by increasing atomic mass to reveal repeating chemical properties, not by alphabetical order, color, physical state, or electrical conductivity.