Question

Nuclides with the same number of neutrons are called:

• A. Isobars
• B. Isotones
• C. Isotopes
• D. Isomers

Hint:

Memory trick:

Iso\textbf{topes} → same pro\textbf{tons}
Iso\textbf{tones} → same neu\textbf{trons}
Iso\textbf{bars} → same mass num\textbf{ber}

Answer 1

The Correct Option is B

Concept: Atomic nuclei are classified based on similarities in proton number, neutron number, or mass number. Key definitions:

Isotopes: Same atomic number (same protons), different neutrons
Isobars: Same mass number, different atomic numbers
Isotones: Same number of neutrons, different protons
Isomers: Same nucleus in different energy states

Step 1: Identify the required condition. The question asks for nuclides having the same number of neutrons.
Step 2: Match with definitions. From standard nuclear terminology:

Same neutrons → Isotones

Step 3: Eliminate other options.

Isobars → Same mass number, not neutrons
Isotopes → Same protons
Isomers → Same nucleus, different energy states

Step 4: Conclusion. Nuclides with equal numbers of neutrons are called isotones.

Answer 2

This question is about the vocabulary nuclear physics uses to classify nuclides by what they share. Since the question specifically asks about nuclides sharing the same neutron count, we can work through each term by checking what quantity it actually refers to.

1. Isobars: The prefix "iso-" means "same," and "-bar" refers to weight, isobars are nuclides that share the same mass number (protons + neutrons combined), while their individual proton and neutron counts can differ. This is not about neutron count specifically, so it's ruled out.
2. Isotones: Isotones are nuclides that share the same number of neutrons while differing in proton number (and therefore in the element itself). This matches exactly what the question describes.
3. Isotopes: This is the most familiar term, isotopes are nuclides of the same element, meaning they share the same number of protons, while differing in neutron number. Since this fixes protons rather than neutrons, it's the opposite pairing from what's asked, so it's ruled out.
4. Isomers: These are nuclides with identical proton and neutron counts (the same nuclide entirely) but existing in different nuclear energy states. Since isomers don't differ in neutron count at all, this doesn't match "same number of neutrons" as a distinguishing feature either, and is ruled out.

Only one term is defined specifically around a shared neutron count while everything else about the nuclide, like the element or proton number, is allowed to vary.

Therefore, the correct answer is Isotones.