Which property is primarily used to organize elements in the modern periodic table?

• A. Number of neutrons
• B. Electronegativity
• C. Atomic mass
• D. Atomic number

Answer: (D)

Verified step by step guidance

1. Understand that the modern periodic table is arranged based on a fundamental property of elements that reflects their identity.
2. Recall that the atomic number represents the number of protons in the nucleus of an atom, which uniquely identifies each element.
3. Recognize that while atomic mass and electronegativity are important properties, they are not the primary basis for the organization of the periodic table.
4. Note that the number of neutrons can vary among isotopes of the same element and thus is not used for the table's arrangement.
5. Conclude that the elements in the modern periodic table are primarily organized by increasing atomic number, ensuring a consistent order based on proton count.