Chapter 39, Problem 27A

(a)

To determine

The ranking of the nuclei by the number of protons in the nucleus.

Explanation of Solution

Introduction:

The number of protons in the nucleus remains same and only number of neutrons changes in the nucleus.

The number of protons in nucleus of the isotopes remain same. So, the number of protons in the nuclei of U-235 and U-238 are equal.

The number of protons in the nucleus are less than the number of protons in the isotopes of uranium because thorium produces due to ejection of radioactive particles from uranium.

Conclusion:

Thus, the ranking of nuclei according to number of proton in nucleus is B = C, A.

(b)

To determine

The ranking of the nuclei by the number of neutrons in the nucleus.

Explanation of Solution

Introduction:

The number of protons in the nucleus depends on the mass number of the atom because mass number is the sum of the number of protons and number of neutrons.

The number of protons remains same and only number of neutrons vary in the radioactive decay.

The higher the mass number higher became the number of neutrons in the nucleus.

The mass number of U-238 is greater than U-235. So, the number of neutrons in the nucleus of U-238 is greater than U-235.

The mass number of U-235 is greater than Th-233. So, the number of neutrons in the nucleus of U-2385 is greater than Th-233.

Conclusion:

Thus, the ranking of nuclei according to number of neutrons in nucleus is C, B, A.

(c)

To determine

The ranking of the atom according the number of electrons surrounds them.

Explanation of Solution

Introduction:

The number of electrons in a normal atom is equal to number of protons in the nucleus of that atom.

The number of electrons in U-238 and U-235 are equal because the number of protons in the nucleus of U-238 and U-235 are equal.

The number of electrons in Th-233 is less than the number of electrons in U-238 and U-235 because the number of protons in the nucleus of U-238 and U-235 is greater than the number of protons in the nucleus of Th-233.

Conclusion:

Thus, the ranking of atoms by the number of electrons in the atom is B = C, A.