Question 1

Which of the following best defines the term 'isotope'?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 2

Bromine-79 has an atomic number of 35 and a mass number of 79. How many neutrons does it have?

Accepted Answer

$$79 - 35 = 44$$

Question 3

Which of the following statements about nuclear stability is correct?

Accepted Answer

Atoms are most stable when they have a balanced ratio of protons to neutrons.

Question 4

Which nuclear reaction represents alpha decay?

Accepted Answer

$$^{238}_{92}U \$$rightarrow ^{234}$$_{90}Th $$+ ^{4}$$_{2}He$$

Question 5

A radioactive isotope has a half-life of 2 days. If you start with 100 grams, how much remains after 6 days?

Accepted Answer

$$100 \div 2^3$ = 12.5$$ grams

Question 6

Which type of radiation requires the most shielding to protect humans?

Accepted Answer

Gamma radiation

Question 7

What happens to the atomic number and mass number when a beta particle is emitted from a nucleus?

Accepted Answer

Atomic number increases by 1, mass number stays the same.

Question 8

Which of the following is a real-world application of carbon dating?

Accepted Answer

Determining the age of ancient artifacts and fossils.

Question 9

If a sample of radioactive material has a half-life of 10 years, how much of a 200 g sample will remain after 30 years?

Accepted Answer

$$200 \div 2^3$ = 25$$ grams

Question 10

Which of the following best describes gamma radiation?

Accepted Answer

It consists of high-energy photons and has no mass or charge.

Question 11

What is the main danger associated with exposure to ionizing radiation?

Accepted Answer

It can cause mutations in DNA, leading to cancer.

Question 12

Which nuclear reaction is an example of positron emission?

Accepted Answer

$$^{22}_{11}Na \$$rightarrow ^{22}$$_{10}Ne + e$$^{+}$$

Question 13

Which of the following statements about fission and fusion is correct?

Accepted Answer

Fission splits heavy nuclei into smaller nuclei, while fusion combines light nuclei to form heavier nuclei.

Question 14

Which isotope is more stable: $$^{238}_{92}U ($$half-life = 4.5 billion years) or $$^{234}_{90}Th ($$half-life = 24 days)?

Accepted Answer

$$^{238}_{92}U is $$more stable because it has a longer half-life.

Question 15

What change occurs in the nucleus when an alpha particle is emitted?

Accepted Answer

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

Question 16

Which of the following is a common use of radioactive isotopes in medicine?

Accepted Answer

Imaging and treating cancerous tumors.

Question 17

Which type of nuclear reaction is responsible for the energy produced in the sun?

Accepted Answer

Fusion of hydrogen nuclei.

Question 18

What is the symbol for a beta particle?

Accepted Answer

$$e^{-}$$

Question 19

Which of the following is a risk associated with radon exposure in homes?

Accepted Answer

Increased risk of lung cancer due to inhalation of radioactive particles.

Question 20

Which of the following best describes the process of nuclear fission?

Accepted Answer

A heavy nucleus splits into two smaller nuclei, releasing energy.

Nuclear Chemistry: Study Guide and Key Concepts

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