Question

question 3 of 41
which of the properties is the unique, defining property of atoms of a particular element?
○ atomic number
○ atomic mass
○ charge
○ isotope

Explanation:

Atomic number (number of protons) uniquely identifies an element. Atomic mass varies with isotopes, charge depends on electron gain/loss, and isotope is a variant of an element, not a defining property. Thus, atomic number is the unique defining property.

Answer:

atomic number