Atoms and radiation

Question 1

What did Ernest Rutherford discover?

Answer 1

The positive nucleus

Question 2

What did Democritus discover?

Answer 2

Atoms - they were indestructible and each element has its own atom (340BC)

Question 3

What is an isotope ?

Answer 3

A different version of an atom of an element that has the same n.o of protons but different n.o of neutrons

Question 4

What is a half life?

Answer 4

Time taken for an amount of radiation from a source to decrease by half

Question 5

What is ionisation?

Answer 5

Radiation taking an electron from an atom or molecule, changing it

Question 6

What did John Dalton discover?

Answer 6

Atomic theory - all matter was made from atoms and atoms are identical in size, chemical properties and mass (1803)

Question 7

What did J.J Thompson discover?

Answer 7

Electrons and the plum pudding model - positive spheres (dough) mixed with negative spheres(fruits) (1897)

Question 8

What did Neils Bohr discover?

Answer 8

Energy levels -electrons orbiting nucleus at certain distances (1932)

Question 9

What did James Chadwick discover?

Answer 9

Neutron - imbalance of the mass and atomic n.o

Question 10

What is the Geiger Muller tube used for?

Answer 10

To measure radioactivity

Question 11

Radioactivity

Answer 11

Emission of ionising radiation from an unstable nucleus trying to become stable

Question 12

Radioisotope

Answer 12

Unstable isotope of an element that decay to other elements by emitting radiation

Question 13

Alpha decay

Answer 13

Particles made up of 2 protons and 2 neutrons from nucleus. It is heavy and slow and can only be absorbed by paper

Question 14

How ionising is alpha decay?

Answer 14

Strongly ionising

Question 15

Beta decay

Answer 15

Emits a fast-moving electron from nucleus and a neutron in nucleus becomes a proton. Absorbed by sheet of aluminium

Question 16

How ionising is beta decay?

Answer 16

Moderatley ionising

Question 17

Gamma decay

Answer 17

Waves of electromagnetic radiation emitted by nucleus. Absorbed by thick sheets of lead or metres of concrete- Can travel long distances in air as they tend to pass through than collide with other atoms. Soon they collide and cause damage

Question 18

How ionising is gamma decay?

Answer 18

Weakly ionising

Question 19

Which radiation changes an element?

Answer 19

Beta and Alpha

Question 20

What happens to the atomic and mass n.o when alpha particle is emitted?

Answer 20

Atomic n.o decreases by 2 and mass n.o. decreases by 4

Question 21

What happens to the atom when beta decay occurs?

Answer 21

N.o of protons increase by 1 and makes atomic positive

Question 22

What are gamma rays getting rid of ?

Answer 22

Excess energy from nucleus

Question 23

What makes half life unreliable?

Answer 23

Decays are random

Question 24

What unit is energy measured in?

Answer 24

Becquerels (Bq)

Question 25

What happens when radioactive nucleus decays to become stable?

Answer 25

The activity decreases as a whole

Question 26

Problem with half life

Answer 26

Activity never reaches zero

Question 27

What does short half life mean?

Answer 27

Activity falls quickly because nuclei is unstable and rapidly decays

Question 28

Why is sources with a short half life dangerous?

Answer 28

It has a high amount of radiation they emit at the start but become safe quickly

Question 29

Why can sources with long half life be dangerous?

Answer 29

Nearby areas can be exposed to radiation for years

Question 30

What happens to objects near radioactive sources ?

Answer 30

They are irradiated to radiation

Question 31

What is unwanted radioactive atoms getting on something called?

Answer 31

Contamination

Question 32

What may happen to the unwanted radioactive atoms?

Answer 32

They may decay, releasing radiation that are harmful

Question 33

What can be used to avoid contamination when handling radioactive sources?

Answer 33

Tongs and gloves

Question 34

What should be done to prevent irradiation?

Answer 34

Store source in lead boxes Wear protective clothing Work behind protective screens

Question 35

What radiation is dangerous outside of the body?

Answer 35

Beta and gamma - penetrate through body and reach delicate organs

Question 36

What radiation is dangerous inside of the body?

Answer 36

Alpha - damage is in localised area

Question 37

What can radiation do to living cells?

Answer 37

Enter and ionise atoms leading to tissue damage

Question 38

What are certain radioactive isotopes useful in the body for?

Answer 38

Injected in body and progress around body by an external detector

Question 39

Example of certain radioactive isotopes useful in the body for?

Answer 39

Gamma

Question 40

How is gamma used to kill cancer cells?

Answer 40

Direct carefully and use the right dosage

Question 41

A risk of radiation in the body

Answer 41

Prolonged radiation exposure can cause future risks and side effects

Question 42

Benefits of radiation in the body

Answer 42

Tracers can be used to diagnose life threatening conditions (small risk of cancer) and radiotherapy can get rid of cancer entirely

Question 43

What letter represents the nucleon number?

Answer 43

A

Question 44

What letter represents the proton number?

Answer 44

Z

Question 45

What happens when atoms emit/absorb electromagnetic radation?

Answer 45

The electrons drop to a lower energy shell