Atomic structure

Question 1

Definition of radio active decay

Answer 1

the process in which unstable nuclei break apart or change, releasing radiation as they do so.

Question 2

who discovered the electron

Answer 2

JJ Thompson

Question 3

Who invented the plum pudding model in 1897

Answer 3

JJ Thompson

Question 4

What order were the subatomic particles discovered in

Answer 4

electron
proton
neutron

Question 5

what does an alpha particle consist of

Answer 5

2 protons and 2 neutrons
the same as a helium nucleus

Question 6

Who discovered the nucleus

Answer 6

Rutherford

Question 7

What experiment did Rutherford conduct to test the plum pudding model

Answer 7

Alpha particle scattering experiment

Question 8

Who was the scientist to change the model after Rutherford

Answer 8

Niels Bohr in 1913

Question 9

Name three conclusions that Rutherford made from the alpha particle scattering experiment

Answer 9

1.atoms are mostly empty space
2.there is a concentration of positive charge in the atom
3. this concentration is very very small

Question 10

Rutherford created which model

Answer 10

the nuclear model

Question 11

Bohrs model was called

Answer 11

The solar system model
also how most people view the atom today

Question 12

Bohr discovered

Answer 12

electron energy levels

Question 13

who discovered the neutron

Answer 13

James Chadwick

Question 14

What did Neils Bohr add to Rutherfords nuclear model

Answer 14

electron orbits

Question 15

How many times bigger is the atom compared to the nucleus

Answer 15

10,000 times

Question 16

what is the radius of an atom

Answer 16

-10
1x 10 metres

Question 17

what defines an element

Answer 17

the number of protons

Question 18

When is a nucleus stable

Answer 18

if it has the same amount of neutrons for the amount of protons it has

Question 19

definition of an isotope

Answer 19

Forms of an element that have the same number of protons but different numbers of neutrons

Question 20

name the three types of ways an unstable nuclei can decay

Answer 20

1. through emitting an alpha particle
2. through emitting a beta particle
3. through emitting a gamma ray
4. in some cases it can emit a single neutron

Question 21

what type of decay happens when a nucleus has too FEW neutrons

Answer 21

Alpha decay

Question 22

why does an unstable nucleus with too FEW neutrons emit alpha decay

Answer 22

because by emitting alpha decay, the nucleus reduces in size and this increases stability

Question 23

what type of radiation is emitted when a nucleus has too MANY neutrons

Answer 23

Beta decay

Question 24

why does beta decay happen when a nucleus has too many neutrons

Answer 24

in beta decay a neutron transforms into a proton and an electron (the electron is the beta decay) so it would get rid of one neutron and make the nucleus more smaller and stable

Question 25

what is a beta particle

Answer 25

an electron that has come from the nucleus (from a neutron) can be written as 0 e -1

Question 26

what can neutrons split into

Answer 26

a positive proton and an electron which is ejected at high speed and carries a lot of energy

Question 27

why type of radiation occurs after beta or alpha decay to "cool the nucleus down"

Answer 27

a gamma ray

Question 28

definition of an energy level

Answer 28

specific amounts of energy that electrons have when they orbit a nucleus is a particular shell electrons that gain energy may move to higher energy levels and electrons that lose energy may move to lower energy levels

Question 29

what type of radiation causes no change to the atomic and mass number

Answer 29

gamma radiation

Question 30

what type of radiation causes the atomic number of the nucleus to increase by one but the mass number stays the same

Answer 30

beta decay

Question 31

what type of radiation causes the mass number to decrease by 4 and the atomic number to decrease by 2

Answer 31

Alpha

Question 32

rank the types of decay in order of most to least ionising power

Answer 32

alpha beta gamma

Question 33

rank the types of radiation in order of penetrating power from highest to lowest

Answer 33

gamma beta alpha

Question 34

name the ranges in air for alpha beta and gamma

Answer 34

alpha = <5 cm beta = ~1 metre gamma = > 1 km

Question 35

what measures all types of radioactive decay

Answer 35

a Geiger Muller tube or a GM tube

Question 36

what type of process is radioactive decay

Answer 36

it is a random process

Question 37

definition of half life

Answer 37

The tim eit takes for half of the unstable nuclei in a sample to decay or for the activity of the sample to halve or for the count rate to halve.

Question 38

what is count rate

Answer 38

the number of decays recorded each second by a detector such as the Geiger Muller tube

Question 39

what would be the amount of a sample remaining after 4 half lives

Answer 39

1/16

Question 40

what model did John Dalton create

Answer 40

the solid sphere model

Question 41

definition of irradiation

Answer 41

exposing objects to beams of radiation, it can damage living cells

Question 42

name 2 advantages of irradiation

Answer 42

sterilisation can be done without high temperatures it can be used to kill bacteria on things that would melt

Question 43

name 2 disadvantages of irradiation

Answer 43

it may not kill all bacteria on an object it can be very harmful - standing in the environment where objects are being treated by irradiation could expose peoples cells to damage and mutation

Question 44

definition of contamination

Answer 44

occurs if an object has a radioactive material introduced into it

Question 45

name 2 things that contamination can be used for

Answer 45

checking for leaks for medical uses like tracers

Question 46

name 2 advantages of contamination

Answer 46

radioactive isotopes can be used as medical and industrial tracers imaging processes can replace some invasive surgical procedures

Question 47

name 2 disadvantages of contamination

Answer 47

radioactive isotopes may not go where they are wanted it can be difficult to ensure that the contamination is fully removed so small amounts of radioisotope may still be left behind

Question 48

definition of to ionise or what is ionising power

Answer 48

to convert an uncharged atom or molecule into a charged particle by adding or removing electrons

Question 49

how is radiation hazardous to the human body

Answer 49

it can ionise chemicals within a body it changes the way cells behave can deposit large amounts of energy which can damage or destroy cells completely can cause mutations

Question 50

what unit of measurement is used to measure activity in the nucleus - the number of decays per second from an unstable nucleus

Answer 50

becquerel (Bq)