Radioactivity

Question 1

What happens when an atom gets excited?

Answer 1

The electrons jump up to another shell. They can’t sustain this energy level and go back down again. This releases a lot of energy.

Question 2

What are the three main types of radiation?

Answer 2

Alpha, beta and gamma.

Question 3

What is radioactive decay?

Answer 3

Where particles give off radiation so that their nucleus can become stable.

Question 4

Can you predict radioactive decay?

Answer 4

No it’s random.

Question 5

What is radioactivity measured in?

Answer 5

Becquerels (Bq) 1 Bq = 1 Decay Per Second

Question 6

A nucleus with more neutrons than usual is more likely to be _______

Answer 6

A nucleus with more neutrons than usual is more likely to be unstable.

Question 7

An alpha particle has the nucleus of a _______ particle.

Answer 7

An alpha particle has the nucleus of a helium particle.

Question 8

What is a beta particle?

Answer 8

An electron that has been ejected from the nucleus at a very high speed.

Question 9

How are beta particles formed?

Answer 9

When a neutron turns into a proton and an electron, the electron gets fired out.

Question 10

What are gamma rays?

Answer 10

Electromagnetic radiation that comes from the nucleus.

Question 11

What are the properties of alpha particles?

Answer 11

Large, not very penetrating, 5cm in air before being stopped, stopped by paper, very ionising

Question 12

What are the properties of beta particles?

Answer 12

Small, medium penetrating, 15cm in air before being stopped, stopped by aluminium, a bit ionising

Question 13

What are the properties of gamma rays?

Answer 13

Tiny, very penetrating, several meters in air before being stopped, stopped by lead, not very ionising

Question 14

What does ionising power OR ionisation mean?

Answer 14

When the radiation causes atoms to lose electrons and become ions

Question 15

When calculating alpha radiation, what do you do?

Answer 15

Atomic number decreases by 2, mass number decreases by 4.

Question 16

When calculating beta radiation, what do you do?

Answer 16

Leave the mass number alone, increase the atomic number by 1.

Question 17

What is half-life?

Answer 17

The time it takes for half of the number of nuclei to decay in a sample.

Question 18

What are the 4 main sources of background radiation?

Answer 18

Rocks like granite, cosmic rays from space, nuclear weapon fallout AND nuclear fallout from disasters.

Question 19

What two sources of background radiation are man-made?

Answer 19

Nuclear weapon testing and nuclear fallout from disasters.

Question 20

What is irradiation?

Answer 20

Where an object is exposed to nuclear radiation.

Question 21

Why would we irradiate an object?

Answer 21

We might want to sterilise the object to kill bacteria. You would do this on an object that’s used in medicine.

Question 22

Does an object become radioactive if it becomes irradiated?

Answer 22

No, it only comes in contact with the radiation not the isotope itself.

Question 23

What is a risk of working with radiation?

Answer 23

It can cause cancerous cells in humans.

Question 24

What are some prevention tactics we can use with radiation?

Answer 24

We can shield ourselves from it (e.g. using lead infused clothes, or lead barriers), we can monitor it using devices like Geiger counters,

Question 25

What is contamination?

Answer 25

Where the object itself becomes radioactive because of contact with the isotope.

Question 26

What happens in nuclear fission?

Answer 26

A neutron is fired at a large atom (usually uranium or plutonium) and it splits. This creates quite a lot of energy.

Question 27

What are the products when a nucleus hits a large atom in fission.

Answer 27

There are two daughter atoms which are roughly the same, two or three nuclei and some gamma radiation.

Question 28

In fission, what is a chain reaction?

Answer 28

Where a fission reaction causes another fission reaction which causes another fission reaction….

Question 29

Where do we use a controlled chain reaction?

Answer 29

In a nuclear power plant.

Question 30

Where do we use an uncontrolled chain reaction?

Answer 30

In nuclear weapons.

Question 31

What is nuclear fusion?

Answer 31

Where two smaller particles come together to make a larger particle, creating energy in the process.

Question 32

What is a natural source of nuclear fusion?

Answer 32

The sun.