How did Dmitri Mendeleev organize the elements to create his periodic table?

• A. By arranging elements according to their electron configurations
• B. By increasing atomic mass and grouping elements with similar chemical properties
• C. By increasing atomic number and arranging elements in alphabetical order
• D. By grouping elements based on their physical state at room temperature

Answer: (B)

Verified step by step guidance

1. Understand the historical context: Dmitri Mendeleev created the periodic table before the discovery of the atomic number and electron configurations, so he could not use these modern concepts to organize elements.
2. Recognize that Mendeleev arranged the elements primarily by increasing atomic mass, which was the best measurable property available at the time.
3. Note that while arranging by atomic mass, Mendeleev also grouped elements with similar chemical properties into columns, creating families of elements with shared characteristics.
4. Understand that Mendeleev left gaps in his table where no known elements fit the pattern, predicting the existence and properties of undiscovered elements.
5. Summarize that Mendeleev's periodic table was organized by increasing atomic mass and by grouping elements with similar chemical properties, which allowed for the prediction of new elements and their properties.