Radioactivity

Question 1

Radioactivity

Answer 1

the spontaneous breaking up of an unstable nucleus with the emission of one or more types of radiation

Question 2

what are alpha particles

Answer 2

a particle that consists of 2 neutrons and 2 protons

Question 3

where is americium 241 used

Answer 3

smoke alarms

Question 4

features of alpha particles

Answer 4

positive - consist of 2 protons and 2 neutrons

not very penetrating - can be stopped by a sheet of paper

Question 5

features of beta particles

Answer 5

negative
formed when a neutron is changed to form a proton plus an electron

more penetrating than alpha - can pass through paper

Question 6

what emits beta particles

Answer 6

carbon-14

Question 7

gamma rays

Answer 7

high energy electromagnetic radiation -

Question 8

source of gamma rays

Answer 8

cobalt-60

Question 9

features of gamma rays

Answer 9

very penetrating - can only be stopped by a thick later of lead
not charged
very dangerous carcinogenic
can be used to cure cancer also
used to sterilise surgical instruments

Question 10

use of cobalt 60 and what kind of radiation Is it

Answer 10

kill tumors - gamma ray

Question 11

use of carbon 14 and what kind of radiation is it

Answer 11

carbon dating - beta

Question 12

use of americium 241 and what kind of radiation is it

Answer 12

smoke alarms - alpha

Question 13

radium 226

Answer 13

emits an alpha particle

mass no. DECREASES by 4 to 222 (because 4 nucleons left)

atomic no. DECREASES by 2 to 86 (because 2 protons left)

Question 14

why is radiation considered a nuclear reaction

Answer 14

radiation is emitted from the nucleus

Question 15

differences between chemical and nuclear reactions

Answer 15

chemical :
- only involve electrons
- no new elements involved
- atoms only rearranged

nuclear :
- form a new element

Question 16

transmutation features

Answer 16

when an atom loses a BETA particle it changes into an atom of the element 1 after it in the periodic table

mass number remains the same

very difficult to do articifically

Question 17

definition of transmutation

Answer 17

the changing of one element to another

very difficult to do artificially

mass number remains the same

Question 18

when an atom loses an ALPHA particle

Answer 18

it changes into the element 2 places BEFORE in the periodic table

the mass number of the parent atom will decrease by 4

Question 19

when an atom loses a GAMMA particle

Answer 19

does not give rise to any new atoms
simply the loss of energy

Question 20

when as atom loses a BETA particle its referred to as…

Answer 20

transmutation

Question 21

isotope defintion

Answer 21

atoms of an element that have
the same atomic number
but different mass numbers
due to different numbers of neutrons

Question 22

what are radio-isotopes

Answer 22

isotopes which are unstable and give out radiation

Question 23

what measures radioactivity

Answer 23

geiger-muller tube

Question 24

examples of half lives

Answer 24

C14 - 5700 years
CO60 - 5.26 years
Po234 - 0.15 milliseconds

Question 25

half life definition

Answer 25

the time taken for half of the nuclei in any given sample to decay - compares rates of decay as emission is purely random

Question 26

isotopes can be..

Answer 26

stable or radioactive

Question 27

uses of radio isotopes

Answer 27

1. archeological use (carbon dating) 2. medical uses (kill tumors and sterilise surgical equipment) 3. Food irradiation (gamma rays kill bacteria and fungi therefore decaying decomposition of fruit etc)