Question 1

Which subatomic particle is responsible for the unique identity of an element, and where is it located in the atom?

Accepted Answer

Proton; in the nucleus

Question 2

A neutral atom of magnesium has an atomic number of 12 and a mass number of 24. How many neutrons does it contain?

Accepted Answer

12

Question 3

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons

Question 4

Given the symbolic notation $$^{37}_{17}\mathrm{Cl}$$, how many protons, neutrons, and electrons are present in this atom?

Accepted Answer

Protons: 17, Neutrons: 20, Electrons: 17

Question 5

Which type of radiation has the greatest penetrating power and requires thick lead or concrete for shielding?

Accepted Answer

Gamma rays

Question 6

What is the balanced nuclear equation for the alpha decay of americium-241?

Accepted Answer

$$^{241}_{95}\mathrm{Am} \$$rightarrow ^{4}$$_{2}\mathrm{He} $$+ ^{237}$$_{93}\mathrm{Np}$$

Question 7

If the half-life of iodine-131 is 8 days, how much of a 100 mg sample remains after 32 days?

Accepted Answer

6.25 mg

Question 8

Which of the following statements about radioisotopes used in medical imaging is correct?

Accepted Answer

They are chosen for their ability to concentrate in specific tissues.

Question 9

A patient receives a 50.0 mCi dose of technetium-99m (half-life = 4.8 hr). How much activity remains after 24 hours?

Accepted Answer

1.56 mCi

Question 10

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

Accepted Answer

Gamma rays can fully penetrate the body and require thick shielding.

Question 11

Which equation correctly represents the beta decay of manganese-56?

Accepted Answer

$$^{56}_{25}\mathrm{Mn} \$$rightarrow ^{0}$$_{-1}\mathrm{e} $$+ ^{56}$$_{26}\mathrm{Fe}$$

Question 12

Which of the following best explains why chlorine-35 is more abundant than chlorine-37?

Accepted Answer

The atomic mass of chlorine is closer to 35, indicating chlorine-35 is more abundant.

Question 13

Which of the following is the correct symbolic notation for an atom with 12 protons, 10 neutrons, and 12 electrons?

Accepted Answer

$$^{22}_{12}\mathrm{Mg}$$

Question 14

Which of the following forms of radiation is a high-energy electron emitted from the nucleus?

Accepted Answer

Beta particle

Question 15

A PET scan uses a radioisotope that emits which type of particle, and what is the result of its interaction with an electron?

Accepted Answer

Positron; produces gamma rays

Question 16

Which of the following units is used to measure the biological effect of radiation on tissue?

Accepted Answer

Sievert (Sv)

Question 17

If a radioactive sample has a half-life of 10 days, what fraction of the original sample remains after 30 days?

Accepted Answer

$$\frac{1}{8}$$

Question 18

Which of the following best describes the use of iodine-131 in medicine?

Accepted Answer

It is used in high doses to treat thyroid cancer.

Question 19

Which of the following is true about the mass of subatomic particles?

Accepted Answer

The mass of a proton and neutron are both approximately 1 amu.

Question 20

Which of the following best explains why rapidly dividing cells are more susceptible to ionizing radiation?

Accepted Answer

Their genetic material is exposed more often during cell division.

Atoms and Radioactivity: Structured Study Notes for GOB Chemistry

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