Radioactivity

What is an isotope?

Same number of protons, different number of neutrons

What will unstable nuclei eventually do?

Decay

Why does alpha decay happen?

There are too many nucleons in the nucleus

What will alpha decay create?

A more stable nucleus (hopefully) and an alpha particle

What is an alpha particle?

Helium

Why does beta decay happen?

There are too many neutrons in the nucleus

What will beta decay create?

A more stable nucleus (hopefully) and a beta particle

What does the neutron in beta decay turn into?

A proton

What is a beta particle?

A high speed ionising electron

What happens to the atomic number in alpha decay?

Decreases by 2

What happens to the atomic number in beta decay?

Increases by 1

Why does gamma decay happen?

There is too much energy in the nucleus

What will gamma decay create?

A more stable nucleus (hopefully) and a gamma ray

What is a gamma ray?

An electromagnetic wave

What is an ion?

An atom that has lost or gained electrons

What is ionising?

Something that can make ions

What is released during ionising?

An electron

What are the dangers of ionising radiation?

DNA mutations, cancer and cell death

What type of decay is stopped by paper?

Alpha

What type of decay is stopped by 5mm of aluminium?

Beta

What type of decay is stopped by 5m of lead or concrete?

Gamma

How can radiation be detected?

Photographic film or a geiger counter

What is background radiation?

The radiation around us in the environment all the time

Give an example of natural sources of radiation:

Rocks, food+drink, cosmic rays, living things

Give an example of man made sources of radiation:

Nuclear power plants, nuclear weapon testing, medical scanners

What is radiation measured in

Bq or Becquerels

What is half-life?

The average time taken for half of the original mass of the sample to decay

What is a use of radiation?

Radiotherapy

Why is gamma used for radiotherapy?

It is highly penetrating so it goes through the body and it has low ionising power to cause more cancer

If something has a long half life is it used inside or outside the body?

Outside

If something has a short half life is it used inside or outside the body?

Inside

Why do we want the activity to drop quickly?

So the person doesn’t absorb too much radiation