Nuclear basics: pick the single WRONG statement from the following concise definitions and facts about nuclides and radiations.

Introduction / Context:
This question checks precise nuclear terminology (isotopes, isobars, isotones) and key radiation facts. Many learners mix up these near-sounding terms, so identifying the single incorrect statement requires recalling exact definitions and the basic behavior of α, β, and γ radiation.

Given Data / Assumptions:

• "Nucleons" means protons + neutrons (mass number A).
• Atomic number Z counts protons; neutron number N = A − Z.
• Radiation penetration order is a standard property in nuclear physics.

Concept / Approach:
Definitions to remember: isotopes (same Z, different N ⇒ different A), isobars (same A, different Z), isotones (same N, different Z). Radiation penetration commonly follows: γ > β > α (with appropriate shielding examples: paper blocks α, thin metal blocks β, dense lead/concrete needed for γ). α-emission reduces A by 4 and Z by 2, as a helium-4 nucleus is emitted.

Step-by-Step Solution:
Check (a): "same A, different Z" → definition of isobars. Correct.Check (b): "same Z, different A" are called isotopes, not "isoters". Hence (b) is wrong.Check (c): γ has highest penetration compared with α and β. Correct.Check (d): α-emission removes 2p+2n ⇒ A decreases by 4. Correct.(e) restates the isotope idea correctly (same element, different N).

Verification / Alternative check:
Periodic table relationships: isotopes share the same chemical behavior due to identical Z (electron configuration for neutral atoms), while differing A affects nuclear stability and decay modes—not the electron shell directly.

Why Other Options Are Wrong:

• (a) Correct definition of isobars.
• (c) Correct trend in penetration power.
• (d) Correct consequence of α-decay.
• (e) Correct paraphrase of isotopes.

Common Pitfalls:
Confusing "isotones" (same N) and "isobars" (same A). Also, inventing nonstandard terms like "isoters" can mislead; the accepted term is "isotopes" for same Z.

Final Answer:
Atoms with the same number of protons (same atomic number Z) but different mass numbers are called isoters.