Which property did Dmitri Mendeleev use to develop and organize his original periodic table?

• A. Atomic mass
• B. Atomic number
• C. Electronegativity
• D. Ionization energy

Answer: (A)

Verified step by step guidance

1. Understand the historical context: Dmitri Mendeleev developed the first widely recognized periodic table in the 19th century before the discovery of the atomic number.
2. Recall that Mendeleev arranged elements based on a property that was known and measurable at the time, which allowed him to predict the properties of undiscovered elements.
3. Identify the property Mendeleev used: he organized elements in order of increasing atomic mass, noticing periodic trends in their chemical properties.
4. Recognize that atomic number, electronegativity, and ionization energy were not used by Mendeleev because atomic number was discovered later, and electronegativity and ionization energy were not well-defined or widely used at that time.
5. Conclude that the key property Mendeleev used to develop and organize his original periodic table was atomic mass.