Which property is unique for each element on the periodic table?

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

Answer: (A)

Verified step by step guidance

1. Understand that each element on the periodic table is uniquely identified by a specific property that distinguishes it from all other elements.
2. Recall that the atomic number represents the number of protons in the nucleus of an atom, and this number is unique to each element.
3. Recognize that atomic mass can vary due to different isotopes, so it is not unique to each element.
4. Note that the number of neutrons can vary even within atoms of the same element (isotopes), so it is not unique.
5. Conclude that the atomic number is the property that uniquely identifies each element on the periodic table.