P1 Flashcards
(190 cards)
1
Q
How has the understanding of atoms changed over time?
A
The understanding of what atoms are has changed through time as different models have been developed and replaced with new evidence from experiments.
2
Q
What is a model in the context of atomic theory?
A
A model is a way of describing something in order to explain the way it behaves.
3
Q
Who were the first philosophers to describe the idea of atoms?
A
Greek and Indian philosophers were the first to try and describe the idea of everything being made up of smaller parts.
4
Q
What did Democritus believe about the smallest piece of matter?
A
Democritus thought that the smallest possible piece would be indivisible and could not be cut any further.
5
Q
What is the Greek word for ‘indivisible’?
A
The Greek word for ‘indivisible’ is atomos.
6
Q
What were atoms initially thought to be?
A
Atoms were initially thought to be tiny spheres that could not be divided before the discovery of the electron.
7
Q
What did later models describe the atom as?
A
Later models described the atom as small solid spheres.
8
Q
What significant discovery did J.J. Thompson make at the end of the 19th Century?
A
J.J. Thompson discovered the existence of electrons.
9
Q
What model did J.J. Thompson propose?
A
Thompson proposed the Plum Pudding model.
10
Q
How was the atom described in the Plum Pudding model?
A
The atom was thought to consist of negatively charged electrons (the ‘plums’) in a positively charged ‘dough’ or ‘pudding’.
11
Q
What did JJ Thomson propose about the structure of the atom?
A
JJ Thomson thought of the atom as being a positively charged mass embedded with small negatively charged electrons - a bit like a plum pudding.
12
Q
Why did it make sense for electrons to be embedded within the atom?
A
It was known that electrons were much smaller than atoms, so it made sense that they should be embedded within the larger atom.
13
Q
What was reasoned about the overall charge of the atom?
A
Since electrons have a negative charge, it was reasoned that the rest of the atom would be positive, making the atom neutral overall.
14
Q
What was the purpose of Rutherford’s Alpha Particle Scattering Experiment?
A
In 1909, a group of scientists were investigating the Plum Pudding model.
15
Q
Who instructed the students to carry out the experiment?
A
Physicist, Ernest Rutherford was instructing two of his students, Hans Geiger and Ernest Marsden.
16
Q
What were the scientists directing at the thin gold foil?
A
They were directing a beam of alpha particles (He2+ ions) at a thin gold foil.
17
Q
What did the scientists expect to happen to the alpha particles?
A
They expected the alpha particles to travel through the gold foil, and maybe change direction a small amount.
18
Q
What were the actual findings of the experiment?
A
Most of the alpha particles passed straight through the foil; some changed direction but continued through; a few bounced back off the gold foil.
19
Q
What was the implication of the bouncing back of alpha particles?
A
The bouncing back could not be explained by the Plum Pudding model, so a new model had to be created.
20
Q
What happens when alpha particles are fired at thin gold foil?
A
Most alpha particles go straight through, some are deflected, and a very small number bounce straight back.
21
Q
What conclusion did Ernest Rutherford draw from the alpha particle experiment?
A
Rutherford made different conclusions based on the findings of the experiment.
22
Q
What was the finding regarding alpha particles passing through gold foil?
A
Most of the alpha particles passed straight through the gold foil.
23
Q
What was observed about a few alpha particles in the experiment?
A
A few alpha particles were deflected from their path but continued through the gold foil.
24
Q
What was the finding about a small number of alpha particles?
A
A small number of alpha particles rebounded.
25
What conclusion can be drawn about the structure of atoms?
Atoms are mostly empty space.
26
What does the nucleus of the atom contain?
The nucleus of the atom has a strong positive charge.
27
What is the nature of the nucleus in an atom?
The atom contains a small, heavy nucleus.
28
What happens when alpha particles are fired at thin gold foil?
Most alpha particles go straight through, some are deflected, and a very small number bounce straight back.
29
What conclusion did Ernest Rutherford draw from the alpha particle experiment?
Rutherford made different conclusions based on the findings of the experiment.
30
What was the finding regarding alpha particles passing through gold foil?
Most of the alpha particles passed straight through the gold foil.
31
What was observed about a few alpha particles in the experiment?
A few alpha particles were deflected from their path but continued through the gold foil.
32
What was the finding about a small number of alpha particles?
A small number of alpha particles rebounded.
33
What conclusion can be drawn about the structure of atoms?
Atoms are mostly empty space.
34
What does the nucleus of the atom contain?
The nucleus of the atom has a strong positive charge.
35
What is the nature of the nucleus in an atom?
The atom contains a small, heavy nucleus.
36
What happens when alpha particles are fired at thin gold foil?
Most alpha particles go straight through, some are deflected, and a very small number bounce straight back.
37
What conclusion did Ernest Rutherford draw from the alpha particle experiment?
Rutherford made different conclusions based on the findings of the experiment.
38
What was the finding regarding alpha particles passing through gold foil?
Most of the alpha particles passed straight through the gold foil.
39
What was observed about a few alpha particles in the experiment?
A few alpha particles were deflected from their path but continued through the gold foil.
40
What was the finding about a small number of alpha particles?
A small number of alpha particles rebounded.
41
What conclusion can be drawn about the structure of atoms?
Atoms are mostly empty space.
42
What does the nucleus of the atom contain?
The nucleus of the atom has a strong positive charge.
43
What is the nature of the nucleus in an atom?
The atom contains a small, heavy nucleus.
44
Who proposed the nuclear model of the atom?
Rutherford proposed the nuclear model of the atom.
45
Where is nearly all of the mass of the atom concentrated?
Nearly all of the mass of the atom is concentrated in the centre of the atom (in the nucleus).
46
What is the charge of the nucleus in the nuclear model?
The nucleus is positively charged.
47
What orbits the nucleus in the nuclear model?
Negatively charged electrons orbit the nucleus at a distance.
48
What model did Rutherford's nuclear model replace?
Rutherford's nuclear model replaced the Plum Pudding model.
49
Why was the nuclear model significant?
The nuclear model could explain experimental observations better than the Plum Pudding model.
50
What model replaced the Plum Pudding model?
The Nuclear model replaced the Plum Pudding model as it could better explain the observations of Rutherford's Scattering Experiment.
51
Who proposed the Bohr Model of the Atom?
The Bohr Model of the Atom was proposed by Danish Physicist, Niels Bohr, in 1913.
52
What did Niels Bohr use to create his model?
He used the Nuclear model to create his model.
53
How do electrons behave in the Bohr model of the atom?
Electrons orbit the nucleus at different distances.
54
What are the different orbit distances called in the Bohr model?
The different orbit distances are called energy levels.
55
How many electrons can orbit in the first energy level?
Up to 2 electrons can orbit in the first energy level.
56
How many electrons can orbit in the second energy level?
Up to 8 electrons can orbit in the second energy level.
57
How many electrons can orbit in the third energy level?
Up to 8 electrons can orbit in the third energy level.
58
What is the Bohr model of the atom?
In the Bohr model of the atom, electrons orbit in distinct energy levels, which are at different distances from the nucleus.
59
Why did the Bohr model become the accepted model?
The Bohr model became the accepted model because it explained experimental findings better than the nuclear model.
60
What processes did the Bohr model explain?
The Bohr model was able to explain the processes of absorption and emission of electromagnetic radiation.
61
How did theoretical calculations using the Bohr model perform?
Theoretical calculations made using the Bohr model agreed with experimental results.
62
How has the understanding of the atom changed over time?
The understanding of the structure of an atom has changed over time as more evidence has been collected.
63
What defines the best model of an atom?
The best model of an atom is the one that can explain the evidence of experiments best.
64
What has happened to atomic models over time?
As more evidence has been collected, the models of the atom have improved.
65
What are atoms?
Atoms are the building blocks of all matter.
66
What is at the center of an atom?
Atoms have a tiny, dense, positively charged nucleus at their centre.
67
What orbits around the nucleus of an atom?
Negatively charged electrons orbit around the nucleus.
68
How does the size of the nucleus compare to the whole atom?
The radius of the nucleus is over 10,000 times smaller than the whole atom.
69
What does the nucleus contain?
The nucleus contains almost all of the mass of the atom.
70
What are the three main parts of an atom?
The three main parts of an atom are protons, neutrons, and electrons.
71
What is an interesting fact about the structure of a Lithium atom?
If drawn to scale, the electrons would be around 100 metres away from the nucleus.
72
What is the structure of a Lithium atom?
The nucleus contains protons and neutrons, while electrons move around the nucleus.
## Footnote
If drawn to scale, the electrons would be around 100 metres away from the nucleus.
73
What are protons?
Protons are positively charged particles with a relative atomic mass of one unit.
74
What are neutrons?
Neutrons have no charge and also have a relative atomic mass of one unit.
75
What is the charge and mass of electrons?
Electrons have a negative charge and almost no mass, specifically 1/2000 the mass of a proton or neutron.
76
What is the size of atoms?
Atoms have a radius of only 1 × 10^-10 m, which is 0.0000000001 m.
77
How many atoms can fit across a thumbnail?
About one hundred million atoms could fit side by side across your thumbnail.
78
What is the significance of the size of atoms?
Atoms are incredibly small, highlighting the vast amount of empty space in an atom.
79
What is density?
Density is defined as the mass per unit volume of a material.
80
What is the relationship between density and mass for low density materials?
Objects made from low density materials typically have a low mass.
81
What is the relationship between density and mass for high density materials?
Similarly sized objects made from high density materials have a high mass.
82
Give an example of low density vs high density materials.
A bag full of feathers is far lighter compared to a similar bag full of metal.
83
How does density compare between a balloon and a small bar of lead?
A balloon is less dense than a small bar of lead despite occupying a larger volume.
84
What is the equation for calculating density?
Density is related to mass and volume by the equation: p = m / V.
85
What do the variables in the density equation represent?
p = density (kg/m3), m = mass (kg), V = volume (m3).
86
How do gases compare to solids in terms of density?
Gases are less dense than solids because the molecules are more spread out.
87
What is density?
Density is defined as the mass per unit volume of a material.
88
What is the relationship between density and mass for low density materials?
Objects made from low density materials typically have a low mass.
89
What is the relationship between density and mass for high density materials?
Similarly sized objects made from high density materials have a high mass.
90
Give an example of low density vs high density materials.
A bag full of feathers is far lighter compared to a similar bag full of metal.
91
How does density compare between a balloon and a small bar of lead?
A balloon is less dense than a small bar of lead despite occupying a larger volume.
92
What is the equation for calculating density?
Density is related to mass and volume by the equation: p = m / V.
93
What do the variables in the density equation represent?
p = density (kg/m3), m = mass (kg), V = volume (m3).
94
How do gases compare to solids in terms of density?
Gases are less dense than solids because the molecules are more spread out.
95
What is density?
Density is defined as the mass per unit volume of a material.
96
What is the relationship between density and mass for low density materials?
Objects made from low density materials typically have a low mass.
97
What is the relationship between density and mass for high density materials?
Similarly sized objects made from high density materials have a high mass.
98
Give an example of low density vs high density materials.
A bag full of feathers is far lighter compared to a similar bag full of metal.
99
How does density compare between a balloon and a small bar of lead?
A balloon is less dense than a small bar of lead despite occupying a larger volume.
100
What is the equation for calculating density?
Density is related to mass and volume by the equation: p = m / V.
101
What do the variables in the density equation represent?
p = density (kg/m3), m = mass (kg), V = volume (m3).
102
How do gases compare to solids in terms of density?
Gases are less dense than solids because the molecules are more spread out.
103
What is density?
Density is defined as the mass per unit volume of a material.
104
What is the relationship between density and mass for low density materials?
Objects made from low density materials typically have a low mass.
105
What is the relationship between density and mass for high density materials?
Similarly sized objects made from high density materials have a high mass.
106
Give an example of low density vs high density materials.
A bag full of feathers is far lighter compared to a similar bag full of metal.
107
How does density compare between a balloon and a small bar of lead?
A balloon is less dense than a small bar of lead despite occupying a larger volume.
108
What is the equation for calculating density?
Density is related to mass and volume by the equation: p = m / V.
109
What do the variables in the density equation represent?
p = density (kg/m3), m = mass (kg), V = volume (m3).
110
How do gases compare to solids in terms of density?
Gases are less dense than solids because the molecules are more spread out.
111
112
What is the formula triangle for density, mass, and volume?
Density = Mass / Volume
113
What are the units of density if mass is in grams and volume in cubic centimeters?
Density will be in g/cm³
114
What are the units of density if mass is in kilograms and volume in cubic meters?
Density will be in kg/m³
115
What happens if a material is more dense than water?
It will sink
## Footnote
Water has a density of 1000 kg/m³.
116
What is the approximate density of air?
1.3 kg/m³
117
What is the approximate density range of wood?
300-800 kg/m³ (depending on species)
118
What is the approximate density of water?
1000 kg/m³
119
What is the approximate density of granite?
2700 kg/m³
120
What is the approximate density of lead?
11300 kg/m³
121
What is the arrangement of molecules in solids and liquids?
In solids and liquids, the molecules are tightly packed together.
122
How do molecules behave differently in liquids compared to solids?
In a liquid, the molecules have enough energy to push past each other.
123
What is the density comparison between solids and liquids?
The density of solids and liquids are roughly the same.
124
What is the arrangement of molecules in solids and liquids?
The molecules in solids and liquids are tightly packed, giving them a high density.
125
How are molecules arranged in gases?
In a gas, the molecules are widely separated.
126
What is the density comparison between gases and solids/liquids?
Gases have significantly lower densities than solids or liquids.
127
How much greater is the distance between gas molecules compared to solids or liquids at room temperature?
The distance between molecules in a gas is roughly ten times (in each direction) the distance between molecules in a solid or liquid.
128
What is the typical density of a gas compared to a solid or liquid?
The density of a gas is typically around one-thousandth (1/1000) of the density of a solid or liquid.
129
What is the density of water?
The density of water is 1000 kg/m3.
130
What is the density of air at sea level and room temperature?
The density of air at sea level and room temperature is 1.3 kg/m3.
131
What are the methods described for determining density?
Methods for regular and irregular objects, and a method for the density of liquids.
132
What is the purpose of a regular and irregular shaped object in density determination?
Objects to use to determine the density.
133
What type of liquid is suitable for determining density?
A suitable liquid (e.g. sugar or salt solution).
134
What is the purpose of a 30 cm ruler?
To measure objects up to 30 cm in length.
135
What is the purpose of a Vernier caliper?
To measure objects up to around 15 cm in length.
136
What is the purpose of a micrometer?
To measure objects up to around 3 cm in length.
137
What is the purpose of a digital balance?
To measure the mass of the objects.
138
What is the purpose of a displacement 'Eureka' can?
To measure the displacement of water of irregular objects.
139
What is the purpose of measuring cylinders?
To measure the volume of liquid.
140
What are the methods described for determining density?
Methods for regular and irregular objects, and a method for the density of liquids.
141
What is the purpose of a regular and irregular shaped object in density determination?
Objects to use to determine the density.
142
What type of liquid is suitable for determining density?
A suitable liquid (e.g. sugar or salt solution).
143
What is the purpose of a 30 cm ruler?
To measure objects up to 30 cm in length.
144
What is the purpose of a Vernier caliper?
To measure objects up to around 15 cm in length.
145
What is the purpose of a micrometer?
To measure objects up to around 3 cm in length.
146
What is the purpose of a digital balance?
To measure the mass of the objects.
147
What is the purpose of a displacement 'Eureka' can?
To measure the displacement of water of irregular objects.
148
What is the purpose of measuring cylinders?
To measure the volume of liquid.
149
What are the methods described for determining density?
Methods for regular and irregular objects, and a method for the density of liquids.
150
What is the purpose of a regular and irregular shaped object in density determination?
Objects to use to determine the density.
151
What type of liquid is suitable for determining density?
A suitable liquid (e.g. sugar or salt solution).
152
What is the purpose of a 30 cm ruler?
To measure objects up to 30 cm in length.
153
What is the purpose of a Vernier caliper?
To measure objects up to around 15 cm in length.
154
What is the purpose of a micrometer?
To measure objects up to around 3 cm in length.
155
What is the purpose of a digital balance?
To measure the mass of the objects.
156
What is the purpose of a displacement 'Eureka' can?
To measure the displacement of water of irregular objects.
157
What is the purpose of measuring cylinders?
To measure the volume of liquid.
158
What is the purpose of a eureka can?
It is an apparatus for measuring the density of irregular objects.
159
What is the first step in measuring density using a eureka can?
Place the object on a digital balance and note down its mass.
160
What should you do after noting the mass of the object?
Fill the eureka can with water up to a point just below the spout.
161
What is the next step after filling the eureka can with water?
Place an empty measuring cylinder below its spout.
162
What should you do with the object after setting up the measuring cylinder?
Carefully lower the object into the eureka can.
163
How do you measure the volume of displaced water?
Measure the volume of the displaced water in the measuring cylinder.
164
What should you do after measuring the volume of displaced water?
Repeat these measurements and take an average before calculating the density.
165
What might an example of a results table include?
It might include columns for mass of the object and average volume of water displaced.
166
What is the first step in determining the density of a liquid?
Place an empty measuring cylinder on a digital balance and note down the mass.
167
What is the second step in determining the density of a liquid?
Fill the cylinder with the liquid and note down the volume.
168
What is the third step in determining the density of a liquid?
Note down the new reading on the digital balance.
169
What is the final step in determining the density of a liquid?
Repeat these measurements and take an average before calculating the density.
170
What might a results table look like for density measurements?
An example of a results table might look like this:
## Footnote
See the provided example in the original text.
171
What is the first step in determining the density of a liquid?
Place an empty measuring cylinder on a digital balance and note down the mass.
172
What is the second step in determining the density of a liquid?
Fill the cylinder with the liquid and note down the volume.
173
What is the third step in determining the density of a liquid?
Note down the new reading on the digital balance.
174
What is the final step in determining the density of a liquid?
Repeat these measurements and take an average before calculating the density.
175
What might a results table look like for density measurements?
An example of a results table might look like this:
## Footnote
See the provided example in the original text.
176
What should be done before taking measurements of mass?
Ensure the digital balance is set to zero.
177
What should you do when measuring the density of a liquid?
Remove the measuring cylinder and zero the balance before adding the liquid.
178
What is a main cause of error in this experiment?
Measurements of length.
179
How can you minimize random errors in measurements?
Take repeat readings and calculate an average.
180
What should you be careful of when placing an irregular object in the displacement can?
Dropping it from a height might cause water to splash, leading to an incorrect volume reading.
181
What safety consideration should be taken into account in this experiment?
Handle glassware carefully.
182
What should be done before taking measurements of mass?
Ensure the digital balance is set to zero.
183
What should you do when measuring the density of a liquid?
Remove the measuring cylinder and zero the balance before adding the liquid.
184
What is a main cause of error in this experiment?
Measurements of length.
185
How can you minimize random errors in measurements?
Take repeat readings and calculate an average.
186
What should you be careful of when placing an irregular object in the displacement can?
Dropping it from a height might cause water to splash, leading to an incorrect volume reading.
187
What safety consideration should be taken into account in this experiment?
Handle glassware carefully.
188
What should not be poured into the measuring cylinder when it is on the electric balance?
Water should not be poured into the measuring cylinder when it is on the electric balance.
## Footnote
This could lead to electric shock.
189
What should you do during the whole experiment?
Make sure to stand up during the whole experiment, to react quickly to any spills.
190
What is a good practice when writing about experiments?
When writing about experiments, a good practice is to take in a lot of information.
