Brainscape's Knowledge GenomeTM

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


See full index

Physics > Atomic structure > Flashcards

Atomic structure Flashcards

1
Q

Radius of an atom

A

1 x 10-10 metres

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

Radius of a nucleus

A

1/10000

Most of mass of atom concentrated in nucleus

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

When might the electron arrangement change?

A

With absorption of electromagnetic radiation (move further from nucleus; higher energy level) or by emission of electromagnetic radiation (move closer to nucleus; lower energy level)

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

Overall electrical charge of an atom

A

Doesn’t have one

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

What is the total number of protons and neutrons in an atom called?

A

Mass number

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

What do you call an atom of the same element with different number of neutrons?

A

An isotope of that element

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

Unstable isotopes

A

decay into other elements and give out radiation from nucleus, try to become more stable- radioactive decay, alpha, beta and gamma

Release neutrons when decay to rebalance atomic and mass numbers.

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

What is ionising radiation?

A

Radiation that knocks electrons off atoms, creates positive ions. Ionising power of a radiation source is how easily it can do this

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

What is activity?

A

The rate at which a source of unstable nuclei decays

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

What is activity measured in?

A

Becquerel (Bq)

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

What is the count rate?

A

Number of decays recorded each second by a detector

Geiger-Muller tube

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

How can nuclear radiation be emitted?

A

Alpha particle
Beta particle
gamma ray
neutron

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

Alpha particle-

A

consists of 2 neutrons and 2 protons, same as helium nucleus

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

Beta particle

A

High speed electron ejected from the nucleus as neutron turns into proton

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

Gamma ray

A

electromagnetic radiation from nucleus

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

How far do alpha particles penetrate and what is their ionising power?

A

Only into a few cm of air and absorbed by sheet of paper

Strongly ionising

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

How far do beta particles penetrate and what is their ionising power?

A

Have range in air of a few metres
Absorbed by aluminium
Moderately ionising

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

How far do gamma rays penetrate and what is their ionising power?

A

Long distance through air, absorbed by thick sheets of lead or metres of concrete.

Weakly ionising

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

When are alpha particles used?

A

In smoke detectors, ionises air particles causing current to flow, if smoke in air- binds to ions, current stop and alarm sounds

20
Q

When are beta particles used?

A

Test thickness of sheets of metal, particles not immediately absorbed by material like alpha radiation would be and do not penetrate as far as gamma rays

21
Q

How are nuclear equations written?

A

Atom before decay-> atom after decay + radiation emitted

22
Q

How is an alpha particle represented by symbol?

A

Helium symbol

look at camera roll

23
Q

How is a beta particle in a symbol?

A

Look at camera roll

24
Q

The emission of different types of nuclear radiation may cause a change in….

A

the mass and/or charge of the nucleus

25
Q

Does alpha or beta cause both the mass and charge of nucleus to decrease?

A

Alpha

26
Q

What does beta decay cause?

A

Charge if nucleus go increase

27
Q

What does the emission of a gamma ray cause?

A

Doesn’t change charge or mass of nucleus

28
Q

Is radioactive decay random?

A

yes

29
Q

What is the half life of a radioactive isotope?

A

Time it takes for number of nuclei if isotope in a sample to halve, or time it takes for count rate from a sample containing the isotope to fall
to half it’s initial level

30
Q

How to work out the half life?

A

Initial activity of a sample is 640 Bq. Calculate final activity as a percentage of initial activity after two half lives.
1 half life = 640/2=320
2 half lives=320/2=160

(160/640)x100=0.25 x100=25

31
Q

What is radioactive contamination?

A

The unwanted presence of materials containing radioactive atoms on other materials. Hazard from contamination is due to decay of contaminating atoms. Type of radiation emitted affects level of hazard

32
Q

What is irradiation?

A

Process of exposing an object to nuclear radiation. Irradiated object doesn’t become radioactive

33
Q

Example of natural radiation

A

Cosmic rays from space, rocks

34
Q

Examples of raditation from human activity

A

Fallout from nuclear explosions or nuclear waste

35
Q

How to avoid radiation

A

Wear gloves and tinges, protective suits

36
Q

Why is it important to publish data?

A

The more we understand, the better we can protect ourselves. Data is peer reviewed, leading to improvements

37
Q

How can the background radiation does be affected?

A

By occupation and/or location

38
Q

What is radiation dose measured in?

A

Sieverts (Sv)

39
Q

How does the half life associate with hazards?

A

Short half life means activity falls quickly, nuclei unstable. and rapidly decay. Sources with short half life are dangerous because of high amount of radiation emitted at start, quickly become safe

Long half life means activity falls more slowly because most nuclei don’t decay for long time. Sits there releasing small amount of radiation for long time. Dangerous bc nearby areas exposed for millions of years

40
Q

What is nuclear radiation used in

A

Medicine for:
exploration of internal organs
Control or destruction of unwanted tissue

41
Q

What are gamma rays used for?

A

Medical tracers

Certain radioactive isotopes injected into people and progress around body followed by external detector.

Iodine-123 absorbed by thyroid gland like normal iodine-127, gives out radiation can be detected. Usually gamma. Passes out without much ionisation. Short half life

42
Q

How is radiotherapy treated using radiation?

A

High does if ionising radiation kills all living cells, treat cancer
Gamma rays directed carefully at right dosage to kill cancer cells without damaging normal cells. Patient feel very ill

43
Q

What is nuclear fission?

A

Splitting of large and unstable nucleus
Spontaneous fission rate, usually for fission to occur unstable nucleus absorb neutron

Neutron undergoing fission splits into 2 small nuclei. equal in size, emits 2 or 3 neutrons plus gamma rays. Energy releases

Kinetic energy

Chain reaction

44
Q

How is a chain reaction controlled in nuclear fission?

A

Nuclear reactor to control energy released. Explosion caused by nuclear weapon cause uncontrolled chain reaction

45
Q

What is nuclear fusion?

A

Joining of 2 light nuclei to form heavier nucleus. Some mass may be converted into energy of radiation

Physics (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions