Isotope counting: how many neutrons are present in the nucleus of Uranium-233 (denoted 92U233)?

Introduction / Context:
Interpreting nuclide notation is a basic skill in nuclear science. The superscript denotes the mass number A (total protons + neutrons), and the subscript is the atomic number Z (protons). The difference A − Z yields the number of neutrons N in the nucleus.

Given Data / Assumptions:

• Nuclide: Uranium-233 with A = 233 and Z = 92 (uranium).
• We want N, the neutron count.

Concept / Approach:
The relationship N = A − Z is universal for nuclides. Using Uranium-233 values gives a straightforward arithmetic result.

Step-by-Step Solution:

Verification / Alternative check:
Compare with Uranium-235, which has N = 235 − 92 = 143, confirming that U-233 has two fewer neutrons than U-235, consistent with isotope definitions.

Why Other Options Are Wrong:

• 92: equals proton number (Z), not neutrons.
• 233: total nucleons, not neutrons alone.
• 325: not physically related to A or Z here.
• 115: incorrect subtraction.

Common Pitfalls:
Mixing up A and Z; forgetting that A includes both protons and neutrons. Always verify with N = A − Z.

Final Answer:
141