Y11 Mock Atoms and Radiation

Question 1

what is mass number

Answer 1

number of protons and neutrons inside the nucleus

Question 2

what is atomic number

Answer 2

number of protons in the nucleus

Question 3

what are isotopes

Answer 3

atoms of the same element with the same number of protons and electrons but a different number of neutrons

Question 4

what year was john daltons atom discovered

Answer 4

1803

Question 5

features of john daltons atom

Answer 5

atoms are tiny spheres
can’t be divided
everything is made from them

Question 6

year of jj thompson atom

Answer 6

1897

Question 7

features of JJ thompson atom

Answer 7

positive matter with electrons embedded
discovered electron
mass is spread throughout the atom
charge is spread throughout the atom

Question 8

year of ernest rutherford atom

Answer 8

1910

Question 9

features of ernest rutherford atom

Answer 9

mass is concentrated at the centre
nucleus is charged
most of the mass is in the nucleus

Question 10

year of niels bohr atom

Answer 10

1913

Question 11

features of niels bohr atom

Answer 11

electrons were in shells orbiting the nucleus

Question 12

year of james chadwick atom

Answer 12

1940

Question 13

features of james chadwick atom

Answer 13

neutrons in the nucleus

Question 14

what do some atoms have

Answer 14

unstable nuclei

Question 15

what is decay

Answer 15

when an unstable nucleus emits radiaiton

Question 16

why is decay random

Answer 16

you cannot say when a nucleus will emit radiation

Question 17

where are alpha particles emitted from

Answer 17

nucleus of a radioactive nuclei

Question 18

features of alpha particles

Answer 18

made from 2 protons and 2 neutrons
2-3cm range in air
stopped by paper
highly ionising

Question 19

where is beta emitted from

Answer 19

when a neutron splits into an electron and a proton

Question 20

features of beta

Answer 20

fast moving electron
can be stopped by a piece of aluminium
1-2m range in air
middle ionising

Question 21

features of gamma

Answer 21

wave of radiation
unlimited range in air
stopped by thick lead and concrete
least ionising

Question 22

what is half life

Answer 22

the time taken for the number of nuclei of the isotope to halve / the time taken for the count rate of a sample containing the isotope to fall to half its initial level

Question 23

what is radioactive contamination

Answer 23

the unwanted presence of materials containing radioactive atoms on other materials

Question 24

hazard of radioactive contamination

Answer 24

due to the decay of the contaminating atoms

Question 25

what is irradiation

Answer 25

the process of exposing an object to nuclear radiation , irradiated objects do not become radioactive

Question 26

where does background radiation come from

Answer 26

natural sources eg rocks and cosmic rays man made sources eg fallout from nuclear weapon testing and nuclear accidents

Question 27

how does the half life of radioactive isotopes affect their risk to health

Answer 27

radioactive substances with short half lives live in the body for a shorter amount of time so have less risks

Question 28

why is gamma used for sterilisation

Answer 28

gamma rays kill bacteria , mold and insects in food long half life has lots of energy alpha is not used as it can pass through plastic and doesn't contain a lot of energy

Question 29

how does radiotherapy work

Answer 29

gamma rays focused directly onto the cancer cells don't kill many other healthy cells

Question 30

how can people protect themselves from radioactive substances

Answer 30

protective clothing should be worn lead barrier be in a different room remote controlled arm