What term describes atoms of the same element with different numbers of neutrons?

• A. Isotope
• B. Ion
• C. Scientific model
• D. Quark

Answer: (A)

This question focuses on variations of atoms within the same element that differ in neutron count. Atoms of the same element have the same number of protons (their atomic number), which defines the element, but the number of neutrons can vary. When you change the neutron number while keeping the protons the same, you get different isotopes of that element. The mass number changes because it’s the total of protons and neutrons, but the chemical behavior stays largely similar since the electron arrangement (which drives chemistry) is determined mainly by the protons and electrons. A different term, ion, would involve a charge due to a change in electrons, not neutrons. Quarks are particles inside protons and neutrons, and a scientific model is a broader concept. So the term describing atoms of the same element with different numbers of neutrons is isotopes.