How did Henry Moseley improve the accuracy of the periodic table?

• A. By classifying elements by their physical state at room temperature
• B. By grouping elements according to their chemical reactivity
• C. By organizing elements based on their atomic mass
• D. By arranging elements in order of increasing atomic number

Answer: (D)

Verified step by step guidance

1. Understand that before Moseley's work, elements were primarily arranged by atomic mass, which sometimes led to inconsistencies in the periodic table's order.
2. Recognize that Henry Moseley used X-ray spectroscopy to study the frequencies of X-rays emitted by elements, which allowed him to determine the atomic number (number of protons) of each element accurately.
3. Know that Moseley discovered a direct relationship between the atomic number and the X-ray frequencies, proving that atomic number is a more fundamental property than atomic mass for organizing elements.
4. Realize that by arranging elements in order of increasing atomic number rather than atomic mass, Moseley corrected previous anomalies and improved the periodic table's predictive power and accuracy.
5. Conclude that Moseley's work led to the modern periodic law: the properties of elements are a periodic function of their atomic numbers, which is the basis for the current periodic table organization.