Chapter U1.14, Problem 13E

Interpretation Introduction

Interpretation:

Thesignificance of the diagonal line on the isotope graph needs to be explained.

Concept introduction:

Many elements are found in their isotopic forms. These elements have more than one form. They differ in their mass numbers. Isotopes have similar chemical properties. Some isotopes are stable while some are unstable. To study the stability of nuclei of isotopes, an isotope graph is plotted for first 95 elements.

Answer to Problem 13E

Correct answer: Option C. the same number of protons as neutrons is correct.

Explanation of Solution

Reason for correct option:

The isotope graph shows isotopes of all first 95 elements found in nature and in periodic table. It shows a diagonal line and many squares marked on it. Each square represents a different isotope.

The diagonal line plotted on the graph represents the points with equal number of protons and neutrons. It helps to find out the stability of an isotope. The squares that lie on the diagonal line represent isotopes with equal number of protons and neutrons.

So, the correct option is C. the same number of protons as neutrons.

Conclusion

Reasons for incorrect options:

A. The same number of protons - The isotope graph is plotted with number of protons versus number of neutrons. So the diagonal line shows equal number of protons and neutrons. It does not show the same number of protons. Hence, this option is not correct.

B. The same number of neutrons - The isotope graph is plotted with number of protons versus number of neutrons. So the diagonal line shows equal number of protons and neutrons. It does not show same number of neutrons. Hence this option is not correct.

D. The same number of protons plus neutrons - The isotope graph is plotted with number of protons versus number of neutrons. So the diagonal line shows equal number of protons and neutrons. It does not show same number of protons plus neutrons. Hence, this option is not correct.