Ion Composition from Atomic Numbers and Charge

Steps:

• Proton number Z = 92, so number of protons = 92.
• Nucleon number A = 235, so number of neutrons = A - Z = 235 - 92 = 143.
• Neutral uranium atom has electrons = Z = 92.
• +2e charge means 2 electrons lost, so electrons = 92 - 2 = 90.
• Total particles = protons + neutrons + electrons = 92 + 143 + 90 = 325.

Why B is correct:

• Total subatomic particles in an ion equal nucleons (A) plus electrons (Z - charge magnitude in units of e), yielding 235 + 90 = 325 per ion definition.

Why the others are wrong:

• A: Counts only nucleons (protons + neutrons = 235), excludes electrons.
• C: Assumes neutral atom total (235 nucleons + 92 electrons = 327).
• D: Overcounts electrons (e.g., 235 + 94 = 329, misapplying charge).

Final answer: B