Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics Paper 1 > 4- Atomic Structure > Flashcards

4- Atomic Structure Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

What did J.J. Thompson do to develop the atom model

A

Came up with the plum pudding model.

Which suggests that atoms are spheres of positive charge with tiny negative electrons stuck in them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What experiment did Rutherford do in 1909

A

The alpha scattering experiment- firing alpha particles at a thin sheet of gold foil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happened in the alpha scattering experiment

A

Most particles went straight through, some were deflected and some came straight back

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What was concluded from the alpha scattering experiment

A

Most of the mass must be concentrated at the centre in a tiny nucleus which must also be positive. Most of the atom is just empty space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What atom model was made due to the alpha scattering experiment

A

The nuclear model which had a positively charged nucleus surrounded by a cloud of negative electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What did Neils Bohr in the development of the atom

A

Said that electrons orbiting the nucleus were at certain distances called energy levels.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How did James Chadwick develop the atom

A

Proved the existence of the neutron which proved the imbalance between the atomic and mass numbers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is radius of the nucleus

A

1 x 10*-14 m

About 10,000 times smaller than the radius of the atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the radius of an atom

A

About 1 x 10*-10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is an isotope

A

Atoms with the same number of protons but a different number of neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is radioactive decay

A

Unstable isotopes can decay into other elements and give out radiation as they try to become more stable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is ionising radiation

A

Radiation that knocks electrons off atoms, creating positive ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is ionising power

A

How easily a radiation source can knock electrons off atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is an alpha particle

A

Two neutrons and two protons

Like a helium nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What r the characteristics of alpha particles

A

Poor penetrating power, stopped quickly, absorbed by a sheet of paper, only travel a few cm in air
Strongly ionising

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What r beta particles

A

A fast moving electron released by the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What r the characteristics of beta radiation

A

Penetrate moderately far in materials, absorbed by sheet of aluminium, travel a few meters in air
Moderately ionising

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What r gamma rays

A

Waves of electromagnetic radiation released by the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What r the characteristics of gamma rays

A

Penetrate far into materials, absorbed by thick lead or metres of concrete, travel long distances in air.
Weak ionising power as they pass through rather than hitting atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How r nuclear equations written

A

Atom before decay —> atom after decay + radiation emitted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is a key rule when writing nuclear equations

A

The total mass and atomic number must be equal on both sides

22
Q

What happens to an atom when it emits an alpha particle

A

The atomic number reduces by 2 and the mass number reduces by 4

23
Q

What happens to the atom in beta decay

A

A neutron in the nucleus turns into a proton

24
Q

What happens to the atom when gamma rays are released

A

Nothing as it is just a way of getting rid of excess energy

25
Q

What can measure the count rate of a radioactive substance

A

A Geiger-Muller tube and counter

26
Q

What is count rate

A

The number of radiation counts reaching the Geiger-Muller tube per second

27
Q

What is half life

A

The time it takes for the amount of radiation emitted by the source (count rate) to half

28
Q

What is activity

A

The rate at which a source decays

29
Q

What is activity measured in

A

Becquerels, Bq

1Bq is 1 decay per second

30
Q

What is half life in terms of radioactive nuclei

A

The time taken for the number of radioactive nuclei in an isotope to halve

31
Q

What does a short half life mean

A

Activity falls very quickly because the nuclei r very unstable and decay rapidly

32
Q

What does a long half mean

A

Activity falls more slowly because most of the nuclei don’t decay for a long time

33
Q

What graph is used to measure half life

A

Activity against time graph

34
Q

How is half life found in a graph

A

Finding the time interval on the bottom axis corresponding to a halving of the activity in the vertical axis

35
Q

What is background radiation

A

Low level radiation that is around us all the time

36
Q

What does background radiation come from

A

Naturally occurring unstable isotopes,
Space- cosmic rays mostly from the sun,
Human activity- nuclear waste or fallout

37
Q

What is radiation dose

A

The risk of harm to body tissues due to exposure to radiation

38
Q

What is radiation dose measured in

A

Sieverts

The dose from background radiation is small so often measured in millisieverts

39
Q

What r ways to reduce the effects of irradiation

A

Keeping sources in lead lined boxes, standing behind barrier or being in a different room and using remote-controlled arms

40
Q

What is contamination

A

Unwanted radioactive atoms getting onto an object

41
Q

What can be worn to reduce chance of contamination

A

Use gloves and tongs, protective suits

42
Q

What is the most damaging radiation on the outside of the body

A

Gamma and beta as they penetrate the skin and can get to organs
Alpha can’t penetrate skin

43
Q

What is most damaging to the inside of the body

A

Alpha r most dangerous because they damage a very localised area.
Beta is less damaging as it absorbed over larger area and some passes out.
Gamma goes straight out

44
Q

What do low doses of radiation cause in the body

A

Can make cells mutate and divide uncontrollably- cancer

45
Q

What do high doses of radiation cause on the body

A

Kills cells causing radiation sickness

46
Q

What can gamma radiation be used for

A

Medical tracers,
Radiotherapy,
Leaky pipes locating

47
Q

What is nuclear fission

A

Used to release energy from large and unstable atoms by splitting them into smaller ones

48
Q

What is formed and released in fission

A

Two new light elements and two or three neutrons

49
Q

How do nuclear weapons work

A

Uncontrolled fission chain reactions that lead to lots of energy being released as an explosion

50
Q

What is nuclear fusion

A

Two light nuclei collide at high speed and join to create a larger, heavier nucleus.
Releases a lot more energy than fission

51
Q

Why haven’t scientists made fusion reactors

A

The temperatures and pressures needed are so high that the reactors would be very expensive and hard to build

Physics Paper 1 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions