Exam 3 Review Key

Exam Objectives

Describe the difference between fusion and fission

Describe alpha, beta, and gamma emissions

Define half life

Perform half life equations

Fill in missing information for nuclear equations

Write nuclear equations when given an element and the type of decay in undergoes

Review Key

What process powers the sun?

Fission

Fusion (correct)

Gamma decay

Electron capture

What process occurs in nuclear power plants?

Fusion

Positron emission

Fission (correct)

Alpha decay

True or False: Fusion joins two light nuclei into one heavier nucleus.

True (correct)

False

True or False: Fission splits a nucleus into smaller parts.

True (correct)

False

Alpha particles have:

2 protons and 2 neutrons (correct)

1 neutron and 1 proton

2 electrons

No charge

Beta particles are:

High-energy helium nuclei

High-energy electrons (correct)

Neutrons

Gamma rays

Gamma radiation is:

Made of particles

Stopped by paper

Electromagnetic waves (correct)

Positively charged

True or False: Gamma rays have the lowest penetrating power

True

False (correct)

What particle has no mass and no charge?

Proton

Neutron

Alpha

Photon (correct)

True or False: Beta radiation is stopped by paper.

True

False (correct)

All of the following describe alpha particles EXCEPT:

Heaviest radiation

Stopped by paper

Made of helium nuclei

Have a negative charge (correct)

All of the following describe beta emission EXCEPT:

Releases high-energy electrons

Stopped by metal

Releases gamma rays (correct)

Involves a neutron turning into a proton

All of the following are characteristics of gamma rays EXCEPT:

No mass

Most penetrating

Particles with charge (correct)

Often emitted with alpha or beta decay

What is the key difference between beta emission and positron emission?

Beta emits a proton; positron emits an electron

Beta releases a negative particle; positron releases a positive one. (correct)

Beta is not a nuclear process

Positron has more mass

What’s the key difference between beta emission and electron capture?

Beta adds electrons; electron capture releases them

Beta happens inside the nucleus; electron capture does not

Beta releases an electron; electron capture absorbs one (correct)

Electron capture emits photons

Half-life is defined as:

Time it takes to stop a reaction

Time it takes for all nuclei to decay

Total time a nucleus remains stable

Time it takes for half of a radioactive sample to decay (correct)

True or False: A longer half-life means a faster decay rate.

True

False (correct)

In a half-life problem, the amount left is called:

Initial quantity

Remaining quantity (correct)

Full mass

Time passed

Which pair is correctly matched?

Alpha — high penetrating power

Beta — helium nucleus

Gamma — electromagnetic wave (correct)

Positron — negative electron

Which shows beta emission?

$\frac{14}{6}C\to\frac{14}{7}N+\frac{0}{-1}e$ (correct)

$\frac{238}{92}U\to\frac{234}{90}Th+\frac42He$

$\frac{60}{27}Co^{\ast}\to\frac{60}{27}Co+\frac00\gamma$

$\frac{11}{6}C+\frac{0}{-1}e\to\frac{11}{5}B$

What completes this nuclear equation for beta decay: $\frac{14}{6}C\to?+\frac{0}{-1}e$

$\frac{14}{5}B$

$\frac{14}{7}N$ (correct)

$\frac{12}{6}C$

$\frac{15}{7}N$

What completes this nuclear equation for alpha decay: $\frac{238}{92}U\to?+\frac42He$

$\frac{234}{90}Th$ (correct)

$\frac{236}{91}Pa$

$\frac{238}{91}Pa$

$\frac{240}{94}Pu$

Which shows alpha emission?

$\frac{14}{6}C\to\frac{14}{7}N+\frac{0}{-1}e$

$\frac{238}{92}U\to\frac{234}{90}Th+\frac42He$ (correct)

$\frac{60}{27}Co^{\ast}\to\frac{60}{27}Co+\frac00\gamma$

$\frac{11}{6}C+\frac{0}{-1}e\to\frac{11}{5}B$

Which shows gamma emission?

$\frac{14}{6}C\to\frac{14}{7}N+\frac{0}{-1}e$

$\frac{238}{92}U\to\frac{234}{90}Th+\frac42He$

$\frac{60}{27}Co^{\ast}\to\frac{60}{27}Co+\frac00\gamma$ (correct)

$\frac{11}{6}C+\frac{0}{-1}e\to\frac{11}{5}B$

What completes this nuclear equation for gamma decay: $\frac{60}{27}Co^{\ast}\to?+\frac00\gamma$

$\frac{60}{27}Co^{\ast}$ (correct)

$\frac{60}{26}Fe^{\ast}$

$\frac{60}{28}Ni^{\ast}$

$\frac{59}{27}Co^{\ast}$