Lesson: Radioactivity

LESSON: RADIOACTIVITY

What is radioactivity?

Multiple Choice

How many neutrons does the isotope of lithium have?

• 3

• 4

• 5

• 8

​Nuclear decay

​is a process that occurs when an unstable atomic nucleus changes into another more stabel nucleus by emitting radiation.

​Alpha Decay

​An alpha particle is made of two protons and two neutrons

​when an atom releases an alpha particle, its atomic number decreases by two.

​Uranium-238 decays to thorium-235 through the process of alpha decay

​Beta Decay

​When beta decay occurs, a neutron in an atom changes into a proton and high-energy electron called a beta particle.

​In beta decay, the atomic number of an atom increases by one because it has gain a proton.

​Gamma Decay

​Gamma rays do not contain particles, but they do contain a lot of energy.

​In fact, gamma rays can pass through thin sheet of lead! because gamma rays do not contain particles.

​The release of gamma rays does not change one element into another element.

Multiple Choice

Complete the nuclear equation and determine the type of decay that is occurring in this reaction.

• alpha

• beta

• gamma

• none

Multiple Choice

What particle completes this reaction?

• alpha particle

• beta particle

• gamma particle

• neutron

Multiple Choice

What is an isotope

• An atom with the same number of neutrons different number of protons

• An atom that has lost or gained an electron

• An atom with the same number of protons, different number of neutrons

• An atom with the same number of electrons and different neutrons

Multiple Choice

Which particle has a negative charge

• Alpha

• Electron

• Proton

• Neutron

Multiple Choice

What type of decay is shown here

²³⁸₉₂U ---> ²³⁴₉₀Th + ⁴₂He.

• alpha

• beta

• gamma

Multiple Choice

Identify the type of nuclear decay shown here

²¹⁴₈₃Bi → ⁰_-1e + ²¹⁴₈₄Po

• alpha

• beta

• gamma

Multiple Choice

When a nucleus undergoes nuclear decay by gamma rays, the atomic number of the element....

• remains the same

•   decreases by one.

• increases by one.

• increases by two.

Multiple Choice

The type of radioactive particle that can be stopped by a sheet of paper is the ____.

• alpha particle

• beta particle

• gamma ray

• uranium

Multiple Choice

The three types of nuclear radiation in increasing order of penetrating power are ____.  

•   alpha, beta, gamma 

• X ray, beta, gamma

• alpha, gamma, beta 

• X ray, gamma, beta 

Multiple Choice

An alpha particle is made up of

• 2 protons and 4 neutrons

• 1 proton and 1 neutron

• 2 protons and 2 neutrons

• 4 protons and 2 neutrons

Multiple Choice

When a substance undergoes beta decay

• The atomic number increases by 1

• The atomic number decreases by 2

• The atomic number does not change

Multiple Choice

What makes something radioactive?

• elements with an atomic number above 81

• an unstable nucleus

• contaminated sewage

• It decays over time

Multiple Choice

An isotope of an element has the same number of _________, but a different number of _________.

• Protons, electrons

• Protons, neutrons

• Electrons, neutrons

Multiple Choice

Which type of radiation releases an electron?

• Alpha radiation

• Beta radiation

• gamma radiation

Multiple Choice

What particle is released when an unstable isotope undergoes alpha radiation?

• an helium nucleus

• an electron

• a photon of light

Multiple Choice

Which charge does alpha particle have?

• positive

• negative

• it has no charge

Multiple Choice

Which charge does a beta particle have?

• positive

• negative

• it has no charge

Multiple Choice

Which charge does gamma radiation have?

• positive

• negative

• it has no charge

Multiple Choice

Name the most penetrating type of radiation.

• alpha

• beta

• gamma

• lambda