How to find an isotope given mass number and neutrons?

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Discussion Overview

The discussion revolves around identifying an isotope based on a given mass number of 111 and a condition of having 5 more neutrons than a reference point. The context includes elements and isotopes, with participants exploring potential answers and clarifying the question's phrasing.

Discussion Character

  • Homework-related
  • Debate/contested

Main Points Raised

  • One participant states that the question implies 5 more neutrons than protons.
  • Another participant expresses uncertainty about the question's clarity and suggests that the answer provided may be incorrect.
  • A third participant provides atomic numbers and half-lives for the potential answers, concluding that only Iodine-111 fits the criteria of having 5 more neutrons than protons.
  • A later reply suggests that the question might refer to the most common isotope of the element, indicating a possible misinterpretation of the original question.

Areas of Agreement / Disagreement

Participants express disagreement regarding the interpretation of the question and the correctness of the proposed answers. There is no consensus on the clarity of the question or the validity of the answers provided.

Contextual Notes

The discussion highlights potential ambiguities in the phrasing of the question, particularly regarding what the "5 more neutrons" refers to, and the lack of reasoning behind some answers. The atomic properties of the elements listed are also discussed, but the relevance of these details remains uncertain.

axer
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Homework Statement


An isotope of which element has a mass number of 111 and has 5 more neutrons
A- Antimonu
B- Cadmium
C- Iodine
D- Tin
E- Xenon

Homework Equations

The Attempt at a Solution


I don't know where to start
 
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It means 5 more neutrons than protons.
 
.Scott said:
It means 5 more neutrons than protons.
Thank you its C lol Thanks got it.
 
You have reported the question leaving out some words apparently - five more neutrons than what?
You give no reasoning but I think your answer has to be wrong on any possible guess of what the question is. I'm afraid #2 is wrong too. And worst of all that the question is wrong as well (which we are getting quite often recently) - none of the options can be a correct answer.
 
epenguin said:
You give no reasoning but I think your answer has to be wrong on any possible guess of what the question is.
The atomic numbers of the possible answers are 51 (Antimony, Sb), 48 (Cd), 53 (I), 50 (Sn), and 54 (Xe). Antimony-111 has a half-life of 75 seconds. Cadmium-111 is stable. Iodine-111 has a half life of 2.5 seconds. Tin-111 has a half-life of 35 minutes. Xenon-111 has a half-life of 0.74 seconds. So all of the possible answers have a possible mass number of 111.
But only one has 5 more neutrons than protons: Iodine-111, with 53 Protons and 58 Neutrons.
 
Sorry, Scott was better than me at guessing what the question was. The most natural reading of the incomplete question was “five more neutrons than the naturally occurring most common isotope“.

You will probably never meet iodine 111 again.
 

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