Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

GCSE Physics > Unit 4 - Atomic Structure > Flashcards

Unit 4 - Atomic Structure Flashcards

1
Q

State why the nuclei of certain atoms/isotopes are unstable

A

The nuclei of certain atoms/isotopes are unstable due to the number of protons and nucleus in the nucleus of an atom

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

What do radioactive isotopes do

Some isotopes are radioactive. What does this mean.

A

(it means that)Their nuclei decay and release radiation

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

What is radioactive decay

A

Radioactive decay is the random process of a radioactive substance giving out radiation from the nuclei of its atoms.

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

Some isotopes/certain atoms have an _______

A

Some isotopes/certain atoms have an unstable nucleus

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

What must the nuclei of atoms do to become stable

A

To become stable the nucleus must release radiation (decay - radioactive decay) in the form of a particle or as an electromagnetic wave

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

Radioactive decay is a totally ______ process

A

Radioactive decay is a totally random process

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

What is activity

A

The activity is the rate at which a source of unstable nuclei decay.

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

Activity is measured in _____

units of activity

A

Activity is measured in becquerel (Bq)

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

Activity is measured in _____

A

Activity is measured in becquerel (Bq)

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

1 Bq =

A

1Bq = 1 decay per second

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

What is a Geiger-Muller tube used for

A

To measure the activity of a radioactive source we can use a Geiger-Muller tube

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

What is count rate

A

Count-rate is the number of decays recorded each second by a detector (such as: Geiger-Muller tube)

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

How is count rate different to activity

A

It must be remembered that the count recorded by the G-M tube will be caused by the radiation from the source plus that due to background radiation.

The activity is the rate at which a source of unstable nuclei decay.

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

When it comes to atoms emitting radiation what can and cant we predict

A

We cannot predict when an atom will give out radiation
We can predict what percentage of the atoms will give out radiation

can’t predict which nucleus will
decay next
or
can’t predict when a (particular)
nucleus will decay

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

What is ionising radiation

A

Radiation that has enough energy to knock of electrons off atoms (to become an ion)

Radiation hits an atom and caused the atom to become an ion - loses/gains electrons

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

When it comes to radiation what is random and what can we predict

A

The process of emitting radiation is completely random

We can predict what percentage of the atoms will give out radiation

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

Who discovered the electron

A

J.J. Thomson

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

Who developed the plum pudding model (of the atom)

A

J.J. Thomson

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

describe the the alpha scattering experiment

A

A beam of alpha particles was aimed at very thin gold foil and their passage through the foil was detected.

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

why was the alpha scattering experiment done

A

Scientists (Rutherford) wanted to know if the plum pudding model was correct, and to find this out they carried out an experiment

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

What did J.J. Thomson do

A

He discovered the electron, and he then developed the Plum Pudding Model (of the atom)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The discovery of the electron led to what?

A

The discovery of the electron led to the plum pudding model of the
atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe the plum pudding model

A

The Plum Pudding Model is a ball of positively charged matter containing negative electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Draw the plum pudding model

A

https://images.twinkl.co.uk/tr/image/upload/t_illustration/illustation/Plum-Pudding-Model—Science-Diagram-KS4.png

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Scientists knew that atoms contained electrons and that electrons had a negative charge They also knew that an atom was electrically neutral overall What did this allow the scientists to deduce about the pudding part of the atom
The pudding part of the atom had a positive charge - it has an equal amount of positive charge as there are negative charge
26
Who did the Alpha-particle scattering experiment
Ernest Rutherford
27
What model of atom was the plum pudding model replaced with
The nuclear model
28
State the results obtained by Mr Rutherford for the Alpha-particle scattering experiment
Most alpha particles went straight through the gold foil without causing damage Some alpha particles ere deflected through small angles About 1 in 8000 of the alpha particles were reflected straight back
29
Using the nuclear model of the atom explain why the alpha particles went in those directions
Most of the atom is empty space therefore the alpha particles could pass through The atom contained a nucleus which was positively charged which deflected the alpha particles Most of the mass of the atom was concentrated in the positively charged nucleus, which caused the alpha particles to be reflected straight back
30
Using the nuclear model, Rutherford devised an equation to predict the proportion of alpha particles that would be deflected though various angles The results of the experiment were the same as the predictions made by Rutherford What was the importance of the experimental results and the predictions being the same
The experimental results proved the predictions were correct
31
Why did the Alpha particle scattering experiment lead to a new model of the atom, called the nuclear model, replacing the 'plum pudding' model
The results of the experiment could not be explained by the plum pudding model therefore a new model had to be produced
32
the difference between the plum pudding model of the atom and the nuclear model of the atom
The Plum Pudding Model is a ball of positively charged matter containing negative electrons the nuclear atom there is a tiny, dense positively charged nucleus at the centre, where most of the mass is concentrated. A cloud of negative electrons surrounds this nucleus - so most of the atom is empty space ___________ while the nuclear model has electrons that are orbiting around this nucleus (centre of the atom), which contains very dense positively charged protons
33
When was: the proton, neutron discovered
Proton - 1917 Neutron - 1932
34
What were atoms thought to be before the discovery of the electorn
Before the discovery of the electron, atoms were thought to be tiny spheres that could not be divided.
35
Describe how the proton and neutron were discovered
Later experiments led to the idea that the positive charge of any nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge. The name proton was given to these particles. The experimental work of James Chadwick provided the evidence to show the existence of neutrons within the nucleus.
36
What did Niels Bohr say in 1913
In 1913, Niels Bohr said that electrons orbit at different (/specific) distances from the nucleus Bohr's work agreed with the results of experiments by other scientists (so it was accepted) These orbits are called energy levels/shells
37
What is the size of radius of an atom
Atoms are very small, having a radius of about 1 × 10-10 metres.
38
Describe the structure of an atom
The atom has a positively charged nucleus. The nucleus has positively charged protons and neutrons which have got no charge. The nucleus is surrounded by negatively charged electrons The electrons are arranged at different distances from the nucleus (different energy levels).
39
What is the size of the radius of an nucleus
The radius of a nucleus is less than 1/10 000 of the radius of an atom
40
How are the electrons in the nucleus arranged
The electrons are arranged at different distances from the nucleus (different energy levels).
41
How might electron arrangement change when radiation is absorbed or emitted
If the atom absorbs (electromagnetic) radiation an electron can move from a lower energy level to a higher energy level (the atom can now emit electromagnetic radiation and the electron returns back to the lower energy level) If the atom emits radiation an electron can move from a higher energy level to a lower energy level
42
how is an alpha particle different from a helium atom
An alpha particle has 2 protons and 2 neutrons whereas a helium atom has 2 protons, 2 neutrons and 2 electrons.
43
State the four types of radiation
Alpha Beta Gamma Neutron
44
Types of nuclear radiation
An alpha particle (α) A beta particle (β) A gamma ray (γ) A neutron (n) https://banner2.cleanpng.com/20180723/qby/kisspng-gamma-ray-symbol-ionizing-radiation-5b5563c7659891.2656795115323227594162.jpg
45
What is an alpha particle
A particle which consists of two protons and two neutrons (IT IS THE SAME AS A HELIUM NUCLEUS)
46
State the charge of an alpha particle
+2
47
penetrating power
Tells us what type of material is required to stop each form of radiation
48
what is ionising power
When radiation collides with atoms, that can cause the atoms to lose electrons and form ions Very strongly ionising means that the radiation can produce a lot of ions when they collide with a material
49
What can stop alpha radiation (penetrating power)
Alpha particles can be stopped by 5cm of air A single sheet of paper Top layer of skin
50
Alpha particle's range in air
Alpha particles are large. They can travel around 5cm in air before they collide with air particles and stop
51
Describe the ionisation ability (ionising power) of an alpha particle
Very Strongly ionising
52
Are alpha particles affected by electric and magnetic fields
Yes
53
How is an atom neutral
An atom contains the same number of positively charged protons as negatively charged electrons (the negative charges on the electrons cancel out the positive charges on the protons, making the overall atom neutral)
54
Is an alpha particle dangerous
Outside the body - No Inside the body - very dangerous
55
What is a beta particle
A beta particle is a high speed electron ejected from the nucleus as a neutron turns into a proton A beta particle is an electron that originates from the nucleus
56
Beta particle's range in air
Beta particles range in air about 1m before stopping
57
How is a beta particle formed (since nucleus of atoms do not contain electrons)
A beta particle is formed inside the nucleus when a neutron changes into a proton and an electron The electron is ejected from the nucleus. This electron is called a beta particle
58
What stops a beta particle (penetrating power)
3mm of Aluminium harder to stop than alpha particle
59
State the ionisation ability of a beta particle
moderately/quite strongly ionising (not as ionising as alpha particles - since they are smaller) ___________ Very weak (since it is smaller)
60
Are beta particles affected by electric and magnetic fields
Yes (any charged particle is affected)
61
Are beta particles dangerous
Yes - but it is more dangerous outside the body than inside the body
62
What is a gamma ray
A gamma ray is a very high energy electromagnetic wave, originating from the nucleus
63
Gama radiation range in air
Gamma radiaiton travels several metres in air before stopping (unlimited - spreads out in air without being absorbed - aqa textbook)
64
What can stop a gamma ray (penetrating power)
Nothing But, thick lead and concrete can reduce its intensity _______________ several centimetres of lead metres of concrete (more than 1m thick)
65
Ionisation ability of a gamma ray (ionising power)
Very weak weakly ionising
66
Is it affected by electric and magnetic fields
No
67
Are gamma rays dangerous
Yes but it is more dangerous outside the body than inside the body
68
Draw the symbol for an alpha particle, beta particle and a gamma ray
α - alpha β - beta https://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Latin_letter_small_capital_Gamma.svg/2185px-Latin_letter_small_capital_Gamma.svg.png - gamma

GCSE Physics (30 decks)

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