Radiation and ionising

Question 1

The history of the atomic structure:

What happened in 1804?

Answer 1

John Dalton agreed with the Greek that matter was made up of tiny spheres that couldn’t be broken up, and the each element was made up of a different type of atom.

Question 2

The history of the atomic structure:

What happened 100 years after 1804?

Answer 2

JJ Thomson discovered that electrons could be removed from atoms. Thomson suggested atoms were spheres of positive charge with tiny negative electrons stuck to them like plums in a pudding.

Question 3

The history of the atomic structure: 
What happened in 1909?
But what happened then?
So what did they realise?
It showed most of the atom was.....

Answer 3

Rutherford and Marsden fired a beam of Alpha particles at thin gold foil. They expected the positively charged alpha particles to be slightly deflected by the electrons in the plum pudding model.
Most of the alpha particles went straight through the sheet but the odd one came back at them .
It meant most of the atoms mass was at the center of a tiny nucleus, realising the nucleus must have a positive charge since it repelled most of the alpha particles. empty space.

Question 4

Describe the nucleus of an atom?
What does it contain?
Describe the rest of the atom… the electrons …
What is the radius of an atom’s nucleus?

Answer 4

Tiny but makes up most of the mass of the atom.
Protons and neutrons, giving it an overall positive charge.
Empty space, whiz around the outside of the nucleus really fast giving the atom its overall size.
10,000 times smaller than the radius of the atom.

Question 5

What is the mass of an electron?

Answer 5

1/2000

Question 6

Atoms have …. charge overall.
The charge on an electron is the …. ….. the charge on a …, but ……
This means the number of protons always equals what?
If some electrons are added or removed the atom becomes what?

Answer 6

same as, proton, opposite
The number of electrons in a neutral atom.
A charged particle called an ion

Question 7

Atoms have …. charge overall.
The charge on an electron is the …. ….. the charge on a …, but ……
This means the number of protons always equals what?
If some electrons are added or removed the atom becomes what?

Answer 7

same as, proton, opposite
The number of electrons in a neutral atom.
A charged particle called an ion

Question 8

What are isotopes?

So they have the same …. number but a different …. number

Answer 8

Atoms with the same number of protons but a different number of neutrons
atomic, mass

Question 9

What is the atomic number?

Answer 9

The number of protons in an atom

Question 10

What is the atomic mass number?

Answer 10

The number of protons + neutrons in an atom

Question 11

What are good examples of isotopes?

Answer 11

Carbon 12 and 14

Question 12

Most elements have …. isotopes, but there is usually only one or two …. ones.
The other isotopes tend to be …..

Answer 12

different, stable.

radioactive

Question 13

What does ‘radioactive isotope’ mean?

Answer 13

An isotope that will decay into other elements and give out radiation

Question 14

Where do atoms give out their radiation from?

What do radioactive substances do for ever no matter what is done to them?

Answer 14

From the nuclei of the atom

Give out radiation

Question 15

What type of process is radioactivity? (fast slow etc)

So if you have 1000 unstable nuclei what can you not do? (2) Because it’s completely not affected by…

Answer 15

Random
Say exactly when they will decay
Make any decay happen
Physical conditions like temp, or by chemical bonding.

Question 16

What do radioactive substances ‘spit out’?

Answer 16

Alpha, beta or gamma radiation

Question 17

When do you detect background radiation?

Where does it come from? (3)

Answer 17

All the time
Naturally occurring unstable isotopes all around us - in the air, food, building materials, and in underground rocks
Radiation from space, cosmic rays, most from the sun
Man-made sources, fallout from nuclear weapons test, nuclear accidents (Chernobyl) or dumped nuclear waste.

Question 18

What are the relative proportions of background radiation?

Radon gas, cosmic rays, rocks and building materials, nuclear industry, medical xrays, food:

Answer 18

51%, 10%, 14%, 1%, 12%, 12%

Question 19

What are the alpha particles?
What is its subatomic composition?
What size are they (2) and how fats do they move?
What does this mean about their penetration ability in a solid, and air?
How ionising are they, and why? Which means what?

Answer 19

Helium nuclei
Two neutrons, two protons
Relatively big and heavy, slow moving
They don’t penetrate very far into materials and are stopped quickly even when travelling through air.
Strongly ionising because of their size, it means they bash into a lot of atoms and knock electrons off them before they slow down which creates a lot of ions = ionising!

Question 20

What are the beta particles? Where are they in terms of their properties?
How fast to they move and how big are they?
What does this mean about their penetration ability in a solid, and air?
How ionising are they?

Answer 20

Electrons, in between alpha and gamma
Quite fast and they’re quite small
They penetrate moderately into materials before colliding, they have a long range in air
Moderately ionising

Question 21

What are the beta particles? Where are they in terms of their properties?
How fast to they move and how big are they?
What does this mean about their penetration ability in a solid, and air?
How ionising are they?

Answer 21

Electrons, in between alpha and gamma
Quite fast and they’re quite small
They penetrate moderately into materials before colliding, they have a long range in air
Moderately ionising

Question 22

Beta particles:
What happens when a beta particle is emitted?
What is the mass and charge of the beta particle which is a ?

Answer 22

A neutron turns into a proton

Virtually no mass, and a charge of -1, electron

Question 23

What are gamma rays?

Answer 23

Very short wave length electromagnetic waves

Question 24

Beta particles:
What happens when a beta particle is emitted?
What is the mass and charge of the beta particle which is a ?

Answer 24

A neutron turns into a proton

Virtually no mass, and a charge of -1, electron

Question 25

What are gamma rays?
How far do they penetrate a material? Air?
How ionising are they? But eventually…
What is the mass and charge of the gamma ray?

Answer 25

Very short wave length electromagnetic waves
Far with out being stopped, pass straight through
Weakly because they tend to pass straight through rather than collide with atoms. … they hit something and do damage

Question 26

What are gamma rays?
How far do they penetrate a material? Air?
How ionising are they? But eventually…
What is the mass and charge of the gamma ray?

Answer 26

Very short wave length electromagnetic waves
Far with out being stopped, pass straight through
Weakly because they tend to pass straight through rather than collide with atoms. … they hit something and do damage
They have no mass and no charge

Question 27

When a nuclei is decayed by an alpha or beta emission what do they do?

Answer 27

Change from one element to a different one

Question 28

Write the alpha decay nuclear equation for Uranium 238 over the proton number, 92….
It goes to thorium
So you do what to work out the new element’s numbers?

Answer 28

238/92 U ( = arrow) 234/90 Th + 4/2 H + 0/0 Gamma ray sign
Take 4 away from the top number and 2 away from the bottom number.

Question 29

Write the beta decay nuclear equation for Carbon 14 over the proton number, 6….
It goes to nitrogen

Answer 29

14/6 C =(arrow) 14/7 + 0/-1 e

Remember if an electron is added a neutron will convert into a proton, so the proton number will go up by 1

Question 30

What happens when alpha and beta pass through a magnetic field?

Answer 30

They are deflected

Question 31

Why are the alpha and beta deflected in opposite directions in a magnetic field?

Answer 31

They have an opposite charge, alpha have a positive charge and beta have a negative charge

Question 32

Why are the alpha and beta deflected in opposite directions in a magnetic field?

Answer 32

They have an opposite charge, alpha have a positive charge and beta have a negative charge

Question 33

Why do alpha particles feel a larger force in a magnetic field?
But why are they deflected less?
Why doesn’t gamma get deflected?
Describe the picture of the deflection of alpha and beta in these fields….

Answer 33

They have a larger charge than beta
They have a greater mass
It’s an EM wave and has no charge so it doesn’t get deflected in electric or magnetic fields
The A particle goes off to the left at a long curve, when B particle quickly begins to turn to the right and twist in an do a spiral .

Question 34

What does your likelihood of suffering from radiation depend on?
What does this depend on?
The higher the …. the more at risk you are of what?

Answer 34

The radiation dose
The type and amount of radiation exposed to
does, developing cancer

Question 35

What does day to day radiation does depend on?

Answer 35

Location and occupation

Question 36

How do underground rocks cause radiation?

Answer 36

Certain rocks like granite can cause higher levels of radiation at the surface especially if they release radioactive radon gas, this tends to get trapped inside people’s houses.

Question 37

How are nuclear industry miners affected by radiation?

How are they protected?

Answer 37

Workers and uranium miners are typically exposed to 10 times the normal amount of radiation
They wear face masks to stop them from touching or inhaling radioactive material, their radiation does are monitored by badges and regular checkups.

Question 38

How are radiographers affected by radiation?

How are they protected?

Answer 38

They work in hospitals using ionising radiation and so have a higher risk of radiation exposure
They wear lead aprons and stand behind lead screens to protect themselves from prolonged exposure.

Question 39

How are radiographers affected by radiation?

How are they protected?

Answer 39

They work in hospitals using ionising radiation and so have a higher risk of radiation exposure
They wear lead aprons and stand behind lead screens to protect themselves from prolonged exposure.

Question 40

How are commercial pilots affected by radiation?

Answer 40

At high altitudes in jet planes the background radiation increases because of more exposure to cosmic rays. So they have an increased risk in getting cancer

Question 41

How are people underground affected by radiation?

Answer 41

Miners for ex’ are closer to rocks which release radon gas.