Question 1

Which of the following statements best describes a radioactive isotope?

Accepted Answer

It has an unstable nucleus and emits radiation to become more stable.

Question 2

Which type of nuclear radiation is the most penetrating and requires lead or thick concrete for shielding?

Accepted Answer

Gamma ($$\gamma) $$radiation

Question 3

A radioactive isotope undergoes alpha decay. Which of the following correctly describes the changes to its nucleus?

Accepted Answer

The atomic number decreases by 2 and the mass number decreases by 4.

Question 4

Which of the following nuclear equations is correctly balanced for the beta decay of $$^{14}_{6}\mathrm{C}$$?

Accepted Answer

$$^{14}_{6}\mathrm{C} \$$rightarrow ^{14}$$_{7}\mathrm{N} $$+ ^{0}$$_{-1}\mathrm{e}$$

Question 5

A sample of cobalt-60 ($$^{60}\mathrm{Co}) $$has a half-life of 5.3 years. If you start with 400 mg, how much remains after 15.9 years?

Accepted Answer

100 mg

Question 6

Which of the following best explains why gamma radiation is more dangerous than alpha or beta radiation when the source is outside the body?

Accepted Answer

Gamma radiation can penetrate deeply into tissues and organs, causing damage throughout the body.

Question 7

Which of the following is a correct statement about the half-life of a radioactive isotope?

Accepted Answer

It is the time required for half of the radioactive atoms in a sample to decay.

Question 8

Which of the following is a real-world application of radioactive tracers in medicine?

Accepted Answer

Using radioactive iodine to assess thyroid function.

Question 9

Which of the following best describes nuclear fission?

Accepted Answer

A large nucleus splits into smaller nuclei, releasing energy and neutrons.

Question 10

A radioactive sample has a half-life of 2 hours. If you start with 16 g, how much remains after 6 hours?

Accepted Answer

2 g

Question 11

Which of the following is NOT a property of alpha particles?

Accepted Answer

They are high-energy electrons.

Question 12

Which of the following best explains why ionizing radiation is dangerous to living organisms?

Accepted Answer

It can knock electrons out of atoms, creating highly reactive ions that damage biological molecules.

Question 13

Which of the following nuclear reactions represents artificial transmutation (bombardment)?

Accepted Answer

$$^{238}_{92}\mathrm{U} $$+ ^{4}$$_{2}\mathrm{He} \$$rightarrow ^{241}$$_{94}\mathrm{Pu} $$+ ^{1}$$_{0}\mathrm{n}$$

Question 14

Which of the following is a correct statement about the biological effects of radiation?

Accepted Answer

The effects depend on the type of radiation, distance from the source, and length of exposure.

Question 15

Which of the following is true about the use of radioactive isotopes in cancer treatment?

Accepted Answer

Radiation is focused on specific tissues or organs to shrink or treat disease.

Question 16

Which of the following best describes nuclear fusion?

Accepted Answer

Small nuclei combine to form a larger nucleus, releasing large amounts of energy.

Question 17

A patient is given a radioactive tracer for a thyroid scan. Which isotope is most likely used and why?

Accepted Answer

Iodine-131, because it is taken up by the thyroid and emits detectable radiation.

Question 18

Which of the following is the correct relationship for the intensity of radiation as a function of distance from the source?

Accepted Answer

$$I_2$$ = $$I_1$$ \left( \frac{$$d_1$$}{$$d_2$$} \$$right)^2$$

Question 19

Which of the following is a common misconception about the half-life of a radioactive isotope?

Accepted Answer

Half-life is the time required for all of the radioactive atoms to decay.

Chapter 11: Nuclear Chemistry – Study Notes

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