anonymous 5 years ago What is the formula to be used for this question? Please solve question no. 50. Give all the steps. The answer is D.

1. anonymous

The radius of a nucleus with atomic number 53 is measured to be $6 * 10^{-15}$ m.

2. anonymous

3. anonymous

Thank you for replying. This was my question paper in the exam and we were not given any values (mass, etc.) or graphs. Is there any other way, may be a formula, to solve this problem? Can you in any way use this formula: R = $R _{0}$ * $\sqrt[3]{A}$ where R => radius of atom, $R _{0}$ is 1.1 * $10^{15}$ and A => atomic mass number.

4. anonymous

I don't think you'd need to do that. You know that the number of protons in the nucleus, and therefore the atomic number, is 53. You can therefore qualitatively guess a neutron to proton ratio of somewhere in the middle of 1:1 and 1.5:1 (maybe 1.25:1) without needing a graph at all. The only response that makes any sense in that regard is something in the 70's (answer D). A test taking strategy: Looking at the answer choices, they seem to vary widely in magnitude. It seems reasonable to conclude, then, that the question is testing a general concept and isn't concerned with an explicit formula or exact calculation. They want to test your understanding that the neutron to proton ratio of atoms increases as atomic number increases. The only answer choice that makes sense in that context is D. Don't just use the formulas mindlessly; think about it! Hope that helps!