Chem Unit 4 - Radioactivity and Nuclear Energy

The nucleus is very __ compared to the volume of an atom.

Small

The nucleus is very ___.

Dense

What is the nucleus made of?

Nucleons

What is the nucleus of an isotope called?

Nuclide

What are most nuclides?

Radioactive

What percentage of known nuclides are nonradioactive?

Less than 10

What are radioactive nuclides called?

Radionuclides

Are radioactive nuclei stable?

No

What is the radioactive nuclei decomposing into smaller nuclei called?

Radioactive decay

Radioactive decay is:

Spontaneous

What does the nuclide decomposing involve?

The nuclide emitting a particle or energy

What occurs during radioactive decay?

Atoms of one element are changed into atoms of a different one.

In order for an element to change into another, the number of protons must?

Change

All nuclides with how many protons are radioactive?

84 or more

How do we describe nuclear changes?

Using nuclear equations

What are the kinds of radioactive decay?

Alpha, beta, gamma, neutron

What happens when an atom loses an alpha particle?

Atomic number decreases by 2, mass number decreases by 4

What element is used to represent alpha decay?

Helium

What does an alpha particle contain?

2 protons, 2 neutrons

Where is the beta particle found?

In the nucleus

How is a beta particle like an electron?

It moves much faster

What are the two types of beta decay?

Minus beta decay, plus beta decay

In beta decay what does a neutron change into?

Proton

What happens during minus beta decay?

Atomic number increases by 1, mass number stays the same

What happens during plus beta decay?

Atomic number decreases by 1, mass number stays the same

What are gamma rays?

High energy protons

When does gamma emission occur?

When the nucleus rearranges

Is there any particle loss or change in composition during gamma emission?

No

When does gamma emission generally occur?

When the nucleus also goes through another kind of decay.

What happens during positron emission?

Atomic number decreases by 1, mass number stays the same

Positrons are:

Anti-electron and have a negligible mass.

How do positrons appear?

They result from a proton changing into a neutron.

How do electron captures occur?

When an inner orbital electron is pulled into the necleus.

Does electron capture involve any particle emission?

No, but the atom changes.

In electron capture:

The proton turns into a neutron

What happens during electron capture?

Atomic number decreases by 1, mass number stays the same

What can alpha decay pass through?

Neither paper, plastic, lead or concrete.

What can beta decay pass through?

Paper, stopped by plastic

What can Gamma rays pass through?

Paper, Plastic, stopped by lead

What can neutron decay pass through?

Paper, Plastic, Lead, stopped by concrete

How do you detect something?

Identifying something it does.

What do radioactive rays cause air to become?

Ionized

What do radioactive rays cause?

Certain chemicals to give off a flash of light when they strike the chemical.

What is a Geiger-Müller Counter?

Electronic instrument used to detect and measure ionization radiation

How does the Geiger-Müller Counter work?

By counting electrons generated when gas atoms are ionized by radioactive rays.

What is another name for the Geiger-Müller Counter?

Scintillation counter

What can a scintillation counter do?

Count the number of flashes per minute certain chemicals give off after being struck by radioactive rays.

All radionuclides in a sample decay at once.

False

Choose the particle having a relative mass of 0 amu and a charge of +1.

Positron

What is a positron?

A positive electron

The atomic particle having a mass of 0 amu and a charge of –1 is a:

Electron

What is half-life?

That period of time in which 50% of the original number of atoms undergoes radioactive decay.

Strontium-90 from radioactive fallout is a health threat because, like ______________, it is incorporated into bone.

Calcium

The half-life of a radionuclide is:

Constant

What does each radionuclide have?

Its own unique half-life.

Even though the number of radionuclides changes, what doesn’t change?

The length of time it takes for half of the number of that radionuclide to decay.

The radionuclide with the _____ half-life will have the _____ number of decayse per minute.

Shortest, greatest

What is another name for object dating?

Radiometric dating

What is radiometric dating?

It measures the amount of radioactive atoms and stable daughter atoms in the rocks.

What is radiometric dating used for?

Determine the ages of rocks and fossils within those rocks.

What are radiotracers?

Substances that contain a small amounts of a radioactive substance called a radionuclide, an isotope that emits radiation.

What are radiotracers used for?

Tracking processes inside the body or other systems because their radiation can be detected from outside.

Which field are radiotracers commonly used in?

Medical

What are nuclear power plants?

They produce steam that powers a generator, creating electricity called nuclear energy.

The ____ energy radiation has, the ____ its effect can be.

More, larger

Ionizing radiation has a deeper effect:

The better it penetrates human tissue.

Which decay penatrates human skin the best? (List)

Gamma > Beta > Alpha

Radiation has a stronger effect when:

There is more ionization

Which decay has the strongest ionization? (List)

Alpha > Beta > Gamma

The radioactive half-life of a radionuclide, the biological half-life of the element, the physical state of the radioactive material, and how dangerous it is to humans is measure in what unit?

Rems

What is somatic damage?

Damage that affects the organism

What can somatic damage lead to?

Sickness or death

When is somatic damage visible?

Immediately or in the future

What does the severity of somatic damage depend on?

The amount of exposure

What is a future effect of somatic damage?

Cancer

What is genetic damage?

Damage that occurs when radiation damages reproductive cells or organs, causing damage to future offspring.