test 2

Question 1

in 1931 scientists thought that atoms contained only protons and electron suggest what happened in 1932 to change the idea that atoms contained only protons and electrons

Answer 1

the discovery of the neutron

Question 2

what is an alpha particle

Answer 2

2 protons and 2 neutrons

Question 3

what is half life

Answer 3

average time taken for a sample to decay by 1 half (how long it takes for half a sample to decay)

Question 4

which one of isotopes could be used as a tracer in medicine explain the reason of ur choice

Answer 4

technetium - 99 relatively short half life gamma radiation is low ionising so low risks of mutation in skin cells

Question 5

some people may be worried about having such a storage site close to the area in which they live explain why

Answer 5

there is a risk of soil and water sources bringing contamination which could cause food + water to be harmful. a leak could cause human cells to mutate which provides an increased risk of cancer

Question 6

the atoms of the three carbon isotopes are the same because…

Answer 6

they have the same number of protons

Question 7

the atoms of the 3 carbon isotopes are different from each other because…

Answer 7

they have diff number of neutrons

Question 8

what is a beta particle and from what part of an atom is it emitted

Answer 8

a beta particle is an electron emitted from the nucleus

Question 9

carbon 14 is constantly being made in the atmosphere yet for most of the last million years the amount of carbon 14 in the atmosphere has not changed how is this possible

Answer 9

carbon 14 is being made at the same rate its decaying

Question 10

use graph b and info above to find max age that lake cuicocha could be

Answer 10

3800+50 =3850

Question 11

state the range of alpha particles in air

Answer 11

2-3cm

Question 12

which type of nuclear radiation is the least ionising

Answer 12

gamma rays

Question 13

what happens to structure of an atom when an atom is ionised

Answer 13

it can loose/gain an electron

Question 14

people working w sources of nuclear radiation risk damaging their health state one precaution they should take to reduce the risk of their health

Answer 14

minimise the time spent exposed to source

Question 15

what is nuclear fission

Answer 15

a larger parent nuclei splits into 2-3 smaller daughter nuclei lots of energy and 2/3 neutrons are released

Question 16

plutonium is one substance used as a fuel in a nuclear reactor for nuclear fission to happen the nucleus must absorb a particle what type of particle must be absorbed

Answer 16

neutron

Question 17

why is there a repulsion between the nuclei of atoms

Answer 17

they are both positively charged so they repel

Question 18

where does nuclear fusion happen naturally

Answer 18

the sun

Question 19

suggest 2 advantages of the fuel used in a fusion reactor compared w plutonium and the other substances used as fuel in a fission reaction

Answer 19

more energy released from 1kg of fuel in fusion
its naturally occuring so its easier to obtain

Question 20

after 36 yrs only 10 g of tritium remains from an original sample of 80g calculate the half life of tritium

Answer 20

36/3 = 12

Question 21

explain what led to the plum pudding model of the atom being replaced by the nuclear model of the atom

Answer 21

The alpha scattering experiment - alpha particles (ox) were fired at gold foil most went straight through so most of atom is empty space however a few particles deflected at extreme angles showing there is a positive nucleus and it has a mass. the plum pudding model has mass and charge spread throughout the atom