atomic structure

Question 1

radius of an atom

Answer 1

1 x 10 - 10 metres

Question 2

how does the radius of the nucleus compare to that of an atom

Answer 2

at least 10 000 times smaller

Question 3

where is most of the mass in an atom concentrated?

Answer 3

the nucleus

Question 4

how are electrons arranged in atoms

Answer 4

energy levels

Question 5

what happens when an electron absorbs electromagnetic radiation

Answer 5

moves to a higher energy level

Question 6

what happens when an electron emits electromagnetic radiation

Answer 6

moves to a lower energy level

Question 7

what is the mass of a proton

Answer 7

1

Question 8

what is the mass of a neutron

Answer 8

1

Question 9

what is the mass of an electron

Answer 9

1/2000 (nearly 0)

Question 10

what is the charge of a proton

Answer 10

1

Question 11

what is the charge of an electron

Answer 11

-1

Question 12

what is the charge of a neutron

Answer 12

0

Question 13

where are protons found

Answer 13

in the nucleus of an atom

Question 14

where are neutrons found

Answer 14

in the nucleus of the atom

Question 15

where are electrons found

Answer 15

in energy levels orbiting the nucleus

Question 16

what is the atomic number

Answer 16

the number of protons

Question 17

what is the mass number

Answer 17

the number of protons and neutrons

Question 18

how do you find the number of neutrons in an atom

Answer 18

mass number - atomic number

Question 19

why do atoms have no overall charge

Answer 19

they have the same number of protons and electrons

Question 20

how do ions get charged

Answer 20

by an atom gaining or loosing electrons

Question 21

how can atoms turn into positive ions?

Answer 21

lose one or more outer electrons

Question 22

what is an isotope?

Answer 22

atoms of the same element with the same number of protons but different number of neutrons

Question 23

what can lead to a scientific model being replaced

Answer 23

new experimental evidence

Question 24

before the electron was discovered atoms were thought to be…

Answer 24

tiny indivisible spheres

Question 25

what discovery led to the plum pudding model

Answer 25

the electron

Question 26

what was the plum pudding model?

Answer 26

a ball of positive charge with negative electrons embedded in it

Question 27

draw the plum pudding model

Answer 27

google it

Question 28

what were the results of the alpha scattering experiment?

Answer 28

most particles passed straight through, some were deflected by small angles, a few deflected by large angles

Question 29

what conclusion was made from the alpha scattering experiment

Answer 29

the mass of an atom was concentrated in the centre (nucleus) and that the nucleus was charged

Question 30

what improvements did neils bohr suggest

Answer 30

electrons orbit at specific distances

Question 31

what was the first subatomic part of the nucleus to be discovered

Answer 31

the proton

Question 32

what did james chadwick discover

Answer 32

the neutron

Question 33

what is radioactive decay

Answer 33

unstable nuclei give out radiation as they change to become different elements that are more stable

Question 34

can we predict when an atom will decay?

Answer 34

no, its a random process

Question 35

what is activity

Answer 35

the rate at which a source decays

Question 36

what are the units for radioactivity

Answer 36

becquerel (Bq)

Question 37

what are the different types of radiation

Answer 37

alpha particle, beta particle, gamma ray, neutron

Question 38

what is an alpha particle

Answer 38

2 neutrons 2 protons

Question 39

what is a beta particle

Answer 39

high speed electron ejected from the nucleus as a neutron turns into a proton

Question 40

how might an alpha particle be represented in a nuclear equation

Answer 40

4
He
2

Question 41

how might a beta particle be represented in a nuclear equation

Answer 41

0
e
-1

Question 42

what is a gamma ray

Answer 42

electromagnetic radiation from the nucleus

Question 43

what is ionising radiation

Answer 43

removes electrons from atoms

Question 44

which type of radiation is the most ionising

Answer 44

alpha

Question 45

which type of radiation is the least ionising

Answer 45

gamma

Question 46

which type of radiation is the most penetrating

Answer 46

gamma

Question 47

which type of radiation is least penetrating

Answer 47

alpha

Question 48

what is a half life

Answer 48

the time it takes for the number of nuclei of the isotope in a sample to halve

Question 49

what is radioactive contamination

Answer 49

radioactive atoms on other materials

Question 50

what is irradiation

Answer 50

exposing an object to nuclear radiation

Question 51

what are the natural sources of background information

Answer 51

rocks and cosmic rays from space

Question 52

what are the man made sources of background radiation

Answer 52

nuclear weapons testing, nuclear accidents

Question 53

what are the uses of radiation in medicine

Answer 53

exploration of internal organs, control or destruction of unwanted tissues

Question 54

what is nuclear fission

Answer 54

the splitting of a large and unstable nucleus

Question 55

what is usually needed for nuclear fission

Answer 55

the unstable nucleus absorbs a neutron