CHEM 104 Module 6: Nuclear Chemistry Exam 2026/2027 UPDATE
1. Which of the following subatomic particles are found in the nucleus and are
collectively referred to as nucleons?
A. Protons and electrons
B. Protons and neutrons
C. Neutrons and electrons
D. Electrons and positrons
Answer: B
Rationale: Nucleons are the particles that inhabit the nucleus, specifically protons and
neutrons.
2. An alpha particle is identical to the nucleus of which element?
A. Hydrogen
B. Lithium
C. Helium
D. Beryllium
Answer: C
Rationale: An alpha particle consists of two protons and two neutrons, which is the same
as a Helium-4 nucleus.
3. What is the charge of a beta particle?
A. +2
B. -1
C. 0
D. +1
Answer: B
,Rationale: A beta particle is a high-speed electron emitted from the nucleus, carrying a -1
charge.
4. Which type of radiation has the highest penetrating power?
A. Alpha particles
B. Beta particles
C. Gamma rays
D. Positrons
Answer: C
Rationale: Gamma rays are high-energy electromagnetic radiation and require thick lead
or concrete to stop.
5. In alpha decay, how does the mass number of the nucleus change?
A. Increases by 2
B. Decreases by 2
C. Stays the same
D. Decreases by 4
Answer: D
Rationale: Since an alpha particle has a mass of 4, the parent nucleus loses 4 units of mass.
6. Which process involves a neutron changing into a proton and an electron?
A. Alpha decay
B. Beta decay
C. Positron emission
D. Electron capture
Answer: B
Rationale: In beta decay, a neutron converts to a proton (which stays in the nucleus) and
an electron (which is ejected).
, 7. What happens to the atomic number of an atom undergoing positron
emission?
A. Increases by 1
B. Decreases by 1
C. Decreases by 2
D. Remains the same
Answer: B
Rationale: Positron emission converts a proton into a neutron, decreasing the atomic
number by 1 while the mass number stays the same.
8. What is the mass number of a gamma ray?
A. 0
B. 1
C. 4
D. -1
Answer: A
Rationale: Gamma radiation is pure energy (photons) and has no mass or charge.
9. If a radioactive isotope has a half-life of 10 days, how much of a 100g sample
remains after 30 days?
A. 50g
B. 12.5g
C. 25g
D. 6.25g
Answer: B
Rationale: 30 days is 3 half-lives. 100 -> 50 -> 25 -> 12.5g.
1. Which of the following subatomic particles are found in the nucleus and are
collectively referred to as nucleons?
A. Protons and electrons
B. Protons and neutrons
C. Neutrons and electrons
D. Electrons and positrons
Answer: B
Rationale: Nucleons are the particles that inhabit the nucleus, specifically protons and
neutrons.
2. An alpha particle is identical to the nucleus of which element?
A. Hydrogen
B. Lithium
C. Helium
D. Beryllium
Answer: C
Rationale: An alpha particle consists of two protons and two neutrons, which is the same
as a Helium-4 nucleus.
3. What is the charge of a beta particle?
A. +2
B. -1
C. 0
D. +1
Answer: B
,Rationale: A beta particle is a high-speed electron emitted from the nucleus, carrying a -1
charge.
4. Which type of radiation has the highest penetrating power?
A. Alpha particles
B. Beta particles
C. Gamma rays
D. Positrons
Answer: C
Rationale: Gamma rays are high-energy electromagnetic radiation and require thick lead
or concrete to stop.
5. In alpha decay, how does the mass number of the nucleus change?
A. Increases by 2
B. Decreases by 2
C. Stays the same
D. Decreases by 4
Answer: D
Rationale: Since an alpha particle has a mass of 4, the parent nucleus loses 4 units of mass.
6. Which process involves a neutron changing into a proton and an electron?
A. Alpha decay
B. Beta decay
C. Positron emission
D. Electron capture
Answer: B
Rationale: In beta decay, a neutron converts to a proton (which stays in the nucleus) and
an electron (which is ejected).
, 7. What happens to the atomic number of an atom undergoing positron
emission?
A. Increases by 1
B. Decreases by 1
C. Decreases by 2
D. Remains the same
Answer: B
Rationale: Positron emission converts a proton into a neutron, decreasing the atomic
number by 1 while the mass number stays the same.
8. What is the mass number of a gamma ray?
A. 0
B. 1
C. 4
D. -1
Answer: A
Rationale: Gamma radiation is pure energy (photons) and has no mass or charge.
9. If a radioactive isotope has a half-life of 10 days, how much of a 100g sample
remains after 30 days?
A. 50g
B. 12.5g
C. 25g
D. 6.25g
Answer: B
Rationale: 30 days is 3 half-lives. 100 -> 50 -> 25 -> 12.5g.
