P4

Question 1

Atom

Answer 1

The smallest possible piece of an element. Has a radius of 0.1nm

Question 2

Nucleus

Answer 2

The center of an atom. Contains protons and neutrons

Question 3

Proton

Answer 3

A positively charged particle found im

the nucleus. Has a relative mass of 1.

Question 4

Neutral

Answer 4

Has no overall charge

Question 5

Neutron

Answer 5

A neutral particle found in the nucleus.

Has no charge and a relative mass of 1.

Question 6

Electron

Answer 6

A negatively charged particle found in
energy levels (shells) around the nucleus.
Has a relative mass of 0

Question 7

Element

Answer 7

A substance made up of only one type
of atom e.g. the element oxygen is only
made up of oxygen atoms

Question 8

Isotope

Answer 8

Atoms with the same number of protons

but different numbers of neutrons.

Question 9

Stable

Answer 9

The protons and neutrons are securely
stuck together in the nucleus - will not
emit radiation

Question 10

Unstable

Answer 10

The nucleus may break apart at some

point and emit radiation

Question 11

Emit

Answer 11

Means to “give out”. Nuclear radiation is

EMITTED from the nucleus

Question 12

Radioactive Decay

Answer 12

When unstable nuclei break apart,

emitting radiation

Question 13

1. What is the radius of an

atom?

Answer 13

1x10-10m

Question 14

2. Describe the structure

of an atom

Answer 14

Positively charged nucleus
surrounded by negatively
charged electrons orbiting
around the nucleus

Question 15

3. What does the mass

number tell us?

Answer 15

The number of protons and

neutrons.

Question 16

4. What does the atomic

number tell us?

Answer 16

The number of protons

Question 17

5. What is an isotope?

Answer 17

Isotopes have the same
number of protons but different
numbers of neutrons.

Question 18

6. What is the activity of a
   radioactive isotope
   measured in?

Answer 18

Becquerel (Ba).

Question 19

7. What do we use to

measure count rate?

Answer 19

Geiger-muller tube.

Question 20

8. What does ionisation

mean?

Answer 20

An atom turns into an ion (charged particle) by losing or

goining an electron

Question 21

9. Name the 4 types of

nuclegr radiation

Answer 21

Alpha, Beta, Gamma and

Neutron

Question 22

10. What is an alpha
    particle made of and
    what is the symbol for it?

Answer 22

Helium nucleus 2 protons 2 neutrons

Question 23

11. What is the mass and
    charge of an alpha
    particle?

Answer 23

Mass = 4
Charge = 2+

Question 24

12. What is a beta
    particle made of and
    what is the symbol for a
    beta particle?

Answer 24

High energy electron

Question 25

13. What is the mass and charge of a beta particle?

Answer 25

``` Mass = 0 Charge = -1 ```

Question 26

Activity

Answer 26

The rate at which a source of unstable nuclei decays. Activity is measured in becquerels (Bq)

Question 27

Ionisation

Answer 27

An atom loses or gains an electron the charges are no longer balanced and the charged atom is called an ion

Question 28

Penetrating Power

Answer 28

A measure of how easy it is for radiation to travel through different materials

Question 29

Half-Life

Answer 29

The time taken for the count rate to halve/number of radioactive nuclei to halve

Question 30

Irradiation

Answer 30

Irraidation is exposing an object to nuclear radiation. The irradiated object does not become radioactive

Question 31

Contamination

Answer 31

When radioactive isotopes end up on other materials. A contaminated object will be radioactive

Question 32

background Radiation

Answer 32

Radiation that exists naturally all around us and is at a low enough level to not be considered a threat

Question 33

Nuclear fission

Answer 33

Nuclear fission is the splitting of a large and unstable nucleus

Question 34

Nuclear fusion

Answer 34

Nuclear fusion is when two small light nuclei join together to make one heavy nucleus

Question 35

Chain reaction

Answer 35

2 or 3 neutrons explode out of a fission reaction and these can collide with other uranium nuclei to cause further fission reactions

Question 36

What is the plum pudding model

Answer 36

An early model of the atom where the atom is a ball of positive charge with negative electrons embedded in it

Question 37

what was the experiment that disproved the plum pudding model

Answer 37

The gold foil/alpha scattering experiment : alpha particles were fired at gold foil. Plum pudding model predicted all would travel straight through ; but some were deflected and some reflected straight back

Question 38

What was the nuclear model of the atom

Answer 38

The model That was proposed after the plum-pudding model, with atoms having a small positively charged nucleus surrounded by electrons

Question 39

WHY was the nuclear model of the atoms proposed

Answer 39

Because the alpha scattering experiment produced evidence that could not be explained by the plum pudding model

Question 40

What happens to the mass number/atomic number during alpha decay

Answer 40

Mass number goes down by 4 | Atomic number goes down by 2

Question 41

What happens to the mass number/atomic number during beta decay

Answer 41

Mass number - no charge | Atomic number goes up by 1

Question 42

What is irradiation used for

Answer 42

Sterilizing food/medical equipment

Question 43

Why is radiation dangerous

Answer 43

Can mutate cells, lead to cancer/radiation and even death

Question 44

What can we do to keep safe around radiation

Answer 44

keep as far away, spend as little time as possible near radioactive source, shield yourself with thick lead/concrete