Which of the following does the periodic table primarily organize?

• A. Compounds based on their chemical reactivity
• B. Elements based on their atomic number
• C. Molecules based on their molecular weight
• D. Isotopes based on their mass number

Answer: (B)

Verified step by step guidance

1. Understand that the periodic table is a systematic arrangement of chemical elements.
2. Recall that elements in the periodic table are organized primarily by their atomic number, which is the number of protons in the nucleus of an atom.
3. Recognize that this organization reflects periodic trends in chemical properties and reactivity of the elements.
4. Note that the periodic table does not organize compounds, molecules, or isotopes; it specifically arranges elements.
5. Conclude that the correct description is that the periodic table organizes elements based on their atomic number.