This Power Point pretty much summarises the Atomic Structure ,Isotopes and Radioactivity.

1. Radioactivity

2. Learning objectives:
To be able to recall and explain the
structure and properties of the
atom.
To be able to recall the three main
types of radiation.
To be able to explain the structure
and properties of the three main
forms of radiation.

3. Everything is made up of miniscule
particles called ATOMS. Inside atoms
are even smaller particles.
Can you name the parts of the atom?
ELECTRONS
orbit the
nucleus
This is the
NUCLEUS.
PROTONS
and
NEUTRONS
are found in
the nucleus

4. There are usually equal numbers of
Protons and Electrons in the atom. WHY?
This is because they carry opposite
charges. If you have an equal number
of + and – charges they will cancel each
other out so we get a balanced or
neutral atom.
PARTICLE RELATIVE
MASS
CHARGEPARTICLE RELATIVE
MASS
CHARGE
Proton 1 +
Neutron 1 0
Electron 0 -

5. Is this a stable
(balanced) atom?
Why?
What is the
MASS NUMBER?
5 (three Protons
& two Neutrons)

6. MASS NUMBER = number of
protons + number of neutrons
SYMBOL
ATOMIC NUMBER =
number of protons

7. RADIOACTIVE MATERIALS
Most atoms are stable. However,
radioactive atoms are not – they are
unbalanced and unstable.
They ‘want’ to become stable
(balanced). So to try to achieve this
state they emit (give out) energy in
the form of radiation.

8. This releases ENERGY. Sometimes a
MASSIVE amount of energy.
Can you think of any examples?
We’ll look at examples and uses in
more detail in another lesson.

9. TYPES OF RADIATION
How many types of radiation are
there and how are they different?
What are they?

10. What do
you notice?
So, what is an
alpha particle?

11. ALPHA
Alpha (α) – an atom decays into a new
atom and emits an alpha particle (2
protons and 2 neutrons)
Alpha radiation is the nucleus of a helium
atom travelling at extremely high speed.
Unstable nucleus New nucleus
Alpha
particle

12. What do
you notice?
The Atomic number
decreases by a value
of 1.

13. Beta (β) – an atom decays into a new
atom by changing a neutron into a
proton and electron. The fast moving,
high energy electron is called a beta
particle.
Unstable
nucleus
New
nucleus
Beta
particle
BETA

14. What do you
notice?
The atomic structure
doesn’t fundamentally
change.

15. GAMMA
Gamma – after α or β decay surplus
energy is sometimes emitted. The atom
itself is not changed. Gamma radiation is
part of the EM Spectrum; a wave with a
very high frequency, very short
wavelength.
Unstable
nucleus
New
nucleus
Gamma
radiation

16. Type of
radiation
Symbol
What is
it made
from?
How far
will it
travel in
air?
What
stops
it?

17. Types of radiation
Alpha (α) – a high speed
helium nucleus is emitted
(2 protons & 2 neutrons).
Beta (β) – the fast moving,
high energy electron is
called a beta particle.
Gamma (γ) – after α or β
decay surplus energy is
sometimes emitted.
Gamma radiation is a wave
with very high frequency
with short wavelength.
Unstable
nucleus
Unstable
nucleus
Unstable
nucleus
New
nucleus
New
nucleus
New
nucleus
Alpha
particle
Beta
particle
Gamma
radiation

18. Type of
radiation
Symbol
What is
it made
from?
How far
will it
travel in
air?
What
stops
it?
Alpha α Helium
nucleus. 2
protons &
2 neutrons
Beta β High speed
electron
Gamma γ High
energy
wave

19. PROPERTIES
Alpha, Beta and Gamma all have
different properties:
• Different strengths
• They travel different distances
• They are stopped by different
materials.DEMO…

20. Radioactivity
α
β
γ
Copy the diagram below and complete the
arrows for each type. Then use the words at
the bottom to construct an explanation in your
own words.
Alpha, Beta, Gamma, Thick lead, Paper,
Aluminium

22. Type of
radiation
Symbol
What is
it made
from?
How far
will it
travel in
air?
What
stops
it?
Alpha α Helium
nucleus. 2
protons &
2 neutrons
Beta β High speed
electron
Gamma γ High
energy
wave
Type of
radiation
Symbol
What is
it made
from?
How far
will it
travel in
air?
What
stops
it?
Alpha α Helium
nucleus. 2
protons &
2 neutrons
cm Air /paper
Beta β High speed
electron
m Aluminium
Gamma γ High
energy
wave
Lots of m Thick lead
&
concrete

23. Quiz
1.What do you call the centre of
an atom?
A) Electron
B) Nucleus
C) Proton
D) Neutron

24. Quiz
2.A stable atom has…
A) Equal numbers of Protons &
Electrons
B) Different numbers of Protons
C) Equal numbers of Electrons &
Neutrons
D) Equal numbers of Protons &
Electrons

25. Quiz
3.How many types of radiation
are there?
A) 3
B) 9
C) 2
D) 4

26. Quiz
4.Radiation is emitted from…
A) All atoms
B) Most atoms
C) Unstable atoms
D) Stable atoms

27. Quiz
5.An alpha particle consists of…
A) 2 protons
B) A high speed electron
C) A wave
D) 2 protons and 2 neutrons

28. Quiz
6.Beta radiation is…
A) 2 protons
B) A high speed electron
C) A wave
D) 2 protons and 2 neutrons

29. Quiz
7.Gamma radiation is…
A) 2 protons
B) A high speed electron
C) A wave
D) 2 protons and 2 neutrons

30. Quiz
8.Alpha is stopped by…
A) Thick lead
B) Thin paper
C) A few cm of air
D) Aluminium

31. Quiz
9.Beta is stopped by…
A) Aluminium
B) Paper
C) Lead
D) Concrete

32. Quiz
10. Gamma is mostly stopped by…
A) A few cm of air
B) Thick lead
C) Aluminium
D) Paper

33. HAVE WE MET THE LEARNING OBJECTIVES?
Can you recall and explain the structure
and properties of the atom?
Do you know the three main types of
radiation?
Are you able to explain the structure and
properties of the three main forms of
radiation?

34. The End
Well Done!

35. Learning objectives:
To be able to recall and explain the
structure and properties of the 3
forms of radiation.
To be able to explain the ionising
properties of the 3 forms of
radiation.
To be able to understand and
explain the term ‘background
radiation’ with examples.

36. ACTIVITY – individual task:
Complete the 12 questions about
Alpha and Beta decay (on the
sheet).
Then stick it into your book.

37. ALPHA & BETA decay answers…
Alpha decay
(i) 92, (ii) 222, (iii) 204 (top) and 82
(bottom), (iv) He.
Beta decay
(i) 91, (ii) 131, (iii) 6 (top) and 3
(bottom), (iv) 24 (top) and 11 (bottom).
Alpha or Beta?
(i) Beta, (ii) Alpha, (iii) Alpha, (iv) Beta.

38. When a charged particle comes
near another atom, it can pull
electrons off the atom.
This slows the particle down. The
atom is then called an ion. If it
has lost electrons, it is a positive
ion.
IONIZING RADIATION
What does this mean?

39. Ionisation
When radiation collides with neutral atoms
or molecules it alters their structure by
knocking off electrons. This will leave
behind IONS – this is called IONISING
RADIATION.
α particle
Electron

40. So, what forms of radiation can
be ionizing?
Only a charged particle such as
an α or a β can be ionizing.
What about Gamma?
Gamma has no ionizing power. But
it is still the most powerful
radiation but passes through most
objects.

41. BACKGROUND RADIATION
Where does radiation come from and
what are the sources of radiation?
ACTIVITY – In pairs/threes:
In your book, make a list of as many
possible sources of radiation you can
think of.
Make sure you consider natural and
man-made sources.

42. A Neutron walks into a
bar and asks the
bartender ‘How much for
a beer?’
The bar tender says…
‘For you sir, no charge’

43. BACKGROUND RADIATION
Radiation is always present in the
environment. We call this ‘background
radiation’. There are many sources of
background radiation, these include:
Natural
Cosmic rays, Food,
Rocks (particularly
granite) & Radon
gas.
Man-made
Hospitals, Nuclear
bombs and testing,
Nuclear power
stations &
accidents

44. Have the LO been met?
To be able to recall and explain the
structure and properties of the 3
forms of radiation.
To be able to explain the ionising
properties of the 3 forms of
radiation.
To be able to understand and
explain the term ‘background
radiation’ with examples.

45. ACTIVITY – individual task:
Complete the pie chart on the
worksheet to represent the
data about background sources
of radiation.
Stick it into your book.

46. Background Radiation
Radon gas
Food
Cosmic rays
Gamma rays
Medical
Nuclear power
13% are
man-made

47. Learning objectives:
To be able to recall and explain the
different forms of background
radiation.
To be able to explain the meaning
of the term ‘isotope’.
To be able to understand and
explain the how ionising radiation
can be damaging to living cells.

50. Isotopes
An isotope is an atom with a different number of neutrons:
Each isotope has 8 protons – if it didn’t then it just
wouldn’t be oxygen any more.
Notice that the mass number is different. How many
neutrons does each isotope have?
A “radioisotope” is simply an isotope that is radioactive
– e.g. carbon 14, which is used in carbon dating.

51. ACTIVITY – group task in
pairs/threes:
Read the information sheet about
the poisoning of the ex spy.
Create a poster to explain how
the ex-spy Alexander Litvinenko
was killed AND why Polonium-210
is so dangerous if ingested.

52. Have the LO been met?
To be able to recall and explain the
different forms of background
radiation.
To be able to explain the meaning
of the term ‘isotope’.
To be able to understand and
explain the how ionising radiation
can be damaging to living cells.

53. The End
Well Done!

54. An atom bumps into a
friend in the street and
says ‘I’ve lost an electron’
The friend says ‘Are you
sure’. The Atom says…
‘Yes, I’m positive’

55. Quick Quiz!
1.What does the term ionization
mean?
2.What types of radiation cause
ionization?
3.What is an isotope?
4.What is a radioisotope?

56. Quick Quiz!
1.What does the term ionization mean?
When charged particles are produced –
either gaining or removing electrons from
particles.
2.What types of radiation cause ionization?
Only Alpha and Beta.
3.What is an isotope? Atoms of the same
element with a different Mass number
(i.e. different numbers of neutrons).
4.What is a radioisotope? An isotope/s of
an element which emits nuclear radiation

57. Learning objectives:
To appreciate that radiation can be
harmful or beneficial.
To be able to explain how radiation
can be used.
To be able to give examples of
some of the common uses.

58. USES OF RADIATION
When we think of radiation, we
think DANGER! Radiation is
dangerous because it damages
the DNA of living cells.
However, there are many ways
which we can use radiation to our
benefit.

59. ACTIVITY – Individual task:
You are going to find out about the
different ways we use radiation.
Read each of the uses described on
the information sheet. In your own
words, write down the key
information and match it up with one
of the diagrams
Stick the picture in your book next
to your description.

60. 1.How does radiation kill cancer cells?
2.What is the benefit of using radiation as
opposed to an operation to remove a tumour?
3.Why does smoke inside the detector trigger
the alarm?
4.Which type of radiation would be used to
measure the thickness of a) Paper, b)
Aluminium foil and C) Sheet steel?
5.Why sterilize plastic medical equipment with
radiation?
6.How could a tracer be used to find a blockage
in a kidney?

61. Have the LO been met?
To appreciate that radiation can be
harmful or beneficial.
To be able to explain how radiation
can be used.
To be able to give examples of
some of the common uses.

62. The End
Well Done!