How did Dmitri Mendeleev organize his periodic table?

• A. By alphabetical order of element names
• B. By the physical state of elements at room temperature
• C. By increasing atomic number and grouping elements by electron configuration
• D. By increasing atomic mass and grouping elements with similar chemical properties

Answer: (D)

Verified step by step guidance

1. Understand the historical context: Dmitri Mendeleev created the periodic table in the 19th century before the discovery of the atomic number and electron configuration concepts.
2. Recognize that Mendeleev arranged elements primarily by increasing atomic mass, which was the best available property to order elements at that time.
3. Note that Mendeleev grouped elements with similar chemical properties into columns (groups), allowing him to predict the existence and properties of undiscovered elements.
4. Understand that Mendeleev's organization was not based on alphabetical order or physical state, but on chemical behavior and atomic mass trends.
5. Summarize that Mendeleev's periodic table was organized by increasing atomic mass and grouping elements with similar chemical properties, which laid the foundation for the modern periodic table.