Terminology of nuclides: what do we call nuclides that have the same mass number but different nuclear charges (different atomic numbers)?

Introduction / Context:
Nuclear nomenclature helps classify nuclides by how they relate in terms of proton and neutron numbers. Three commonly tested terms are isotopes, isobars, and isotones. Distinguishing them quickly is essential for reaction bookkeeping and interpreting nuclear charts.

Given Data / Assumptions:

• We compare nuclides by mass number A, atomic number Z, and neutron number N.
• The specific case is “same mass number but different Z.”

Concept / Approach:
Isotopes share the same Z (protons) but have different N → same element, different mass numbers. Isobars share the same A (total nucleons) but have different Z and N → different elements with equal mass number. Isotones share the same N (neutrons) but different Z and A. The term matching “same A, different Z” is therefore “isobars.”

Step-by-Step Solution:
Identify the defining equality: A is the same.Recognize that Z is different; hence N must differ to keep A constant.Select “Isobars” as the correct classification.

Verification / Alternative check:
Examples include 40Ar (Z=18, N=22) and 40Ca (Z=20, N=20): same A=40, different Z; these nuclides are isobars.

Why Other Options Are Wrong:
Isotopes: same Z, not same A.Isotones: same N, not same A.None of these: incorrect because “isobars” is the standard term.

Common Pitfalls:
Memorizing terms without associating them with A, Z, and N; mixing up “iso-” prefixes.

Final Answer:
Isobars