Paper One Flashcards
(186 cards)
1
Q
Describe John Dalton’s model of the atom
A
A solid sphere that could not be divided into smaller parts. There were no subatomic particles.
2
Q
What was the first subatomic particles discovered?
A
Electrons
3
Q
What are electrons?
A
Tiny negatively charged subatomic particles
4
Q
Describe the plum pudding model
A
A cloud of positive charge with negative electrons in bedded in it
5
Q
What model came after Dalton’s model?
A
The plum pudding model
6
Q
Describe the alpha scattering experiment
A
Alpha particles were fired at a thin piece of gold foil. Some of these alpha particles bounce back resulting in the discovery of a solid sub-particle. This became known as the nucleus of the atom.
7
Q
What came after the plum pudding model?
A
The alpha scattering experiment
8
Q
What came after the alpha scattering experiment?
A
The nuclear model
9
Q
What did the nuclear model suggest?
A
Electrons orbit around the nucleus, but not at set distances
10
Q
What came after the nuclear model?
A
The electron shell model by Niels Bohr
11
Q
What did Bohr calculate?
A
Electrons must orbit the nucleus at fix distances on shells or energy levels
12
Q
What came after the Bohr model?
A
The proton discovery
13
Q
What was discovered in the proton experiments?
A
The nucleus contain smaller positive particles called protons
14
Q
What came after the proton discovery?
A
The discovery of the neutron
15
Q
Who’s experiments revealed that there was another particle?
A
James Chadwick
16
Q
What subatomic particle did James Chadwick find?
A
A particle with no charge that became known as a neutron
17
Q
What conclusion was made after the discovery of a neutron?
A
Protons and neutrons are in the nucleus and electrons orbit the nucleus in shells
18
Q
What is relative mass?
A
The mass of one thing compared to another
19
Q
What two subatomic particles are both given the relative mass of one?
A
Proton and neutron
20
Q
Why is the relative mass of a single electron considered to be zero?
A
They are so small, that it will take 2000 electrons to equal the mass of a single proton
21
Q
What is the radius of an atom?
A
1 x 10^-10 m
22
Q
How many times smaller than atoms are nuclei?
A
10,000
23
Q
What is the radius of a nucleus?
A
1 x 10^-14 m
24
Q
What is the relative charge of a proton?
A
+1
25
What is the relative charge of a neutron?
0
26
What is the relative charge of an electron?
-1
27
How do I calculate the number of protons in an element from the periodic table?
The number of protons equals the atomic number
28
How do I calculate the number of neutrons in an element from the periodic table?
Mass number - atomic number
29
How do I calculate the number of electrons in an element from the periodic table?
It is the same as the proton, the atomic number
30
How do atoms have no overall charge?
They have the same number of protons and electrons making them neutral
31
What does the top number in a periodic table element represent?
Relative atomic mass
32
What do the letters mean in an element from the periodic table?
Atomic symbol
33
What does the bottom number represents on an element from the periodic table?
Atomic number
34
When drawing atoms, how many electrons can go on the first shell?
2
35
When you are drawing in atoms, how many electrons can go on the second shell, and every shell after?
8
36
Define an element
Substances made of one type of atom. Each atom of an element will have the same number of protons.
37
Define compounds
Compounds are made of different types of atoms chemically bonded together. The atoms in a compound have different numbers of protons.
38
Define an isotope
Atoms of the same element that have different numbers of neutrons, but the same number of protons.
39
What is meant by abundance?
The percentage of atoms within a certain mass
40
How do I calculate relative atomic mass of isotopes?
(Isotope 1 abundance * isotope 1 mass) + (isotope 2 abundance * isotope 2 mass) / 100
41
Define a mixture
Two or more elements or compounds that are not chemically bonded together
42
How can substances in a mixture be separated?
Physical processes that do not need to use chemical reactions
43
When is filtration used?
Separating mixtures that are made of insoluble solids and a liquid
44
When is crystallisation used?
Separate a soluble solid from a solution in a mixture
45
When is simple distillation used?
To separate a solvent from a solution in a mixture
46
When is fractional distillation used?
To separate two liquids with similar boiling points in a mixture
47
When is paper chromatography used?
To identify substances from a mixture, in a solution
48
What is covalent bonding?
When electrons are shared between non-metal atoms
49
What is a single bond in covalent bonding?
When each atom shares one pair of electrons
50
What is a double bond in covalent bonding?
When each atom shares two pairs of electrons
51
What are the three covalent structures?
Giant covalent, small molecules and large molecules
52
Give an example of a giant covalent structure
Diamond
53
What is a giant covalent structure?
Many billions of atoms, each one with a strong covalent bond to a number of others
54
Give an example of small covalent molecule
Water
55
What is a small covalent molecule?
Each molecule contains only a few atoms with strong covalent bonds between the atoms. The different molecules are held together by weak intermolecular forces.
56
Give an example of a large covalent molecule
Polymers
57
What is a large covalent molecule?
Mini repeating units joined by covalent bonds to form a chain. Separate chains are held together by intermolecular forces that are stronger than in small molecules.
58
What are the properties of giant covalent structures?
High melting and boiling points, because lots of energy is needed to break the strong covalent bonds. They are solid at room temperature.
59
What are the properties of small covalent molecules?
Low melting and boiling points because little energy is needed to break the weak intermolecular forces. They are normally gaseous or liquid at room temperature.
60
What are the properties of large covalent molecules?
Melting and boiling points that are between giant covalent and small molecules, because they have stronger, intermolecular forces and small molecules which requires more energy to overcome. They’re normally solid at room temperature.
61
What is graphite?
Graphite is a giant covalent structure, but is different to other giant covalent substances
62
What is the structure of graphite?
It’s made of only carbon, each forming three bonds to other carbon atoms and forms hexagonal rings in layers.
63
Why is graphite used in pencils?
The layers are able to slide over each other because they are not covalently bonded, leaving marks on paper.
64
Why is graphite conductive?
Each carbon atom has one spare electron which is delocalised. A delocalised electron can carry a charge through the structure.
65
What is graphene?
A single layer of graphite
66
What is a fullerene?
Hollow cages of carbon atoms bonded together in one molecule. They can be arranged as a sphere or as a tube. The molecules are held together by weak intermolecular forces, so they can slide over each other. They conduct electricity.
67
What is the fullerene sphere called and how many carbon atoms make it?
Buckminster fullerene with 60 carbon atoms
68
Give a use of fullerenes like the Buckminster fullerene
Lubricants and drug delivery
69
What are carbon nanotubes?
Carbon atoms arranged in cylindrical tubes. They are difficult to break when pulled apart.
70
What is the use of carbon nanotubes?
Electronics
71
What is an ion?
An atom has lost or gained electrons to give them a full outer shell
72
Why do ions have a charge?
The number of electrons is no longer equal to the number of protons
73
What is the charge of an ion that has gained electrons?
Negative
74
What is the charge of an ion that has lost electrons?
Positive
75
What is ionic bonding?
The transfer of electrons between a nonmetal atom and a metal atom. The metal atom will always lose electrons while the nonmetal atom will always gain electrons.
76
What type of structure is formed in ionic bonding?
Giant ionic lattice
77
How are the ions attracted to each other?
Electrostatic force of attraction
78
What are the properties of ionic bonding?
Ionic substances have high melting points because the electrostatic force of attraction requires lots of energy to break. Solid ionic substances do not conduct electricity because the ions are in a fixed position. When melted or dissolved, ionic substancesdo conduct electricity because the ions are free to move and carry a charge.
79
What is metallic bonding?
The atoms make up metals form layers. Electrons in the outer shells of the atom are delocalised. The positive metal ions are than attracted to these delocalised electrons by the electrostatic force of attraction
80
Define malleable
Soft; able to bend
81
Why are metals malleable?
They made of layers that can slide over each other
82
Why are metals good conductors of electricity and thermal energy?
Delocalised electrons are free to move through the structure
83
Why do metals have high melting and boiling points?
The electrostatic attraction between the metal ions and delocalised electrons is strong so lots of energy is needed to break it
84
What is an alloy and why is it made?
An alloy is one metal ions are added to those of a different element. Pure metals are often too soft, so they need to become an alloy to create a harder mixture.
85
How do you create an alloy?
Metal ions are added to another element to disturb the regular arrangement of the layers which prevents them from sliding over each other.
86
How many elements are listed in the modern periodic table?
Approximately 100
87
How are elements ordered in Mendeleev’s periodic table?
Normally by atomic mass, but some elements were swapped around
88
How are elements ordered in the modern periodic table?
By atomic number
89
Why where the gaps in Mendeleev’s periodic table?
For undiscovered elements
90
How are elements grouped in Mendeleev’s periodic table?
By chemical properties
91
How are elements group in the modern periodic table?
By number of electrons on the outer shell
92
How are metals and nonmetals organised in Mendeleev‘s periodic table?
There was no clear distinction
93
How are metals and nonmetals organised in the modern periodic table?
Metals or to the left, nonmetals to the right
94
What were the problems with Mendeleev’s periodic table?
It was incomplete, with no explanation for why some elements had to be swapped to fit into appropriate groups
95
How did the discovery of electrons assist the making of the periodic table?
It allows scientists to work out the elements of the same number of electrons on the outer shell had similar chemical properties
96
How did the discovery of protons assist the making of the periodic table?
It allowed the scientist to order their periodic table by atomic number
97
How did the discovery of neutrons assist the making of the periodic table?
The discovery of neutrons led to the discovery of isotopes. Isotopes explain why some elements didn’t seem to fit when the periodic table was organised by atomic mass
98
What is the collective name for the elements in group 0?
Noble gases
99
What are the properties of the noble gases?
They had full outer shell is making them inert. This means they exist as single atoms as they do not bond to form molecules. The boiling points increase down the group.
100
What is the collective name of group 1 elements?
The alkali metals
101
What are the properties of group 1 elements?
Reactivity increases as you go down the group. There is more shielding as you go down the group, making it easier to lose the one outershell electron.
102
Why are group 1 elements so reactive?
They only need to lose one electron to have a full outer shell
103
What happens when a group 1 elements react with water?
It forms an alkali, a solution of their metal hydroxide
104
What is the collective name for group 7 elements?
The halogens
105
What are the halogens?
Non-metals that exist as molecules made up of pairs of their own atoms
106
What happens to melting and boiling point as you go down group 7?
It increases
107
What happens to reactivity as you go down group 7?
It decreases
108
Why does reactivity decrease as you go down group 7
Atoms become bigger, causing more shielding. This makes it harder to pull in the electron needed to form a full outer shell.
109
What is group 7 displacement?
More reactive group 7 elements can take the place of less reactive ones in a compound. For example, fluorine displaces chlorine as it is more reactive.
110
What is the law of conservation of mass?
Mass cannot be destroyed or created
111
Why does the mass appear to decrease in some reactions?
A gas is produced and is lost to the surroundings
112
Why does the mass appear to increase in some reactions?
One or more of the reactants was a gas and has become a liquid or solid
113
What does aqueous mean?
Dissolved in water
114
What is the state symbol for aqueous?
(aq)
115
What is the state symbol for a gas?
(g)
116
What is the state symbol for a liquid?
(l)
117
What is the state symbol for a solid?
(s)
118
What is the relative formula mass (Mr)?
Sum of all the atomic masses in the formula. For example, the Mr of water (H2O) is 1 + 1 + 16 =18
119
What is meant by Avogadro constant?
One mole of a substance contains 6.02×10^23 atoms, ions or molecules.
120
In simple terms, what is meant by Avogadro constant?
One mole of a substance has the same mass as the Mr of the substance.
For example, Mr of H2O = 18 so 18g of water contains 6.02×10^23 molecule so one mole of water is 18g.
121
What is the equation to calculate moles?
Moles = mass / Mr (Mass crushing poor old Mr Mole)
122
What is meant by excess and limiting reactants?
In a chemical reaction between two or more reactants, often one of the reactants will run out before the others. The reactant leftover is in excess. The reactant that runs out is the limiting reactant.
123
How do you work out which reactant is limiting, and which is in excess?
Write the balance symbol equation
Pick one of the reactants and it’s quantity has given in the question
Use the ratio of the reactants in the balanced equation to see how much the other reactant you need
124
What is concentration?
Concentration is the amount of solute in a volume of solvent. It is measured in g/dm^3
125
What is the equation to find concentration?
Concentration (g/dm^3) = mass (g) / volume (dm^3)
126
How do I convert from volume in centimetres cubed to decimetres cubed?
Divide by 1000
127
What is high concentration?
Lots of solute in little solution
128
What is low concentration?
Lots of solute in little solution
129
Define the reactivity of metal
How chemically reactive it is
130
What happens to high reactivity metals when they are added to water?
They react very vigourously
131
What is the reactivity series?
The placement of metals in order of the reactivity
132
What metals is electrolysis used to extract?
Potassium, sodium, lithium, calcium, magnesium and aluminium
133
What metals do we need to use reduction with carbon to extract?
Zinc, iron, tin, lead and copper
134
What metals are mined from the earths crust?
Gold and silver
135
Why can we mine pure gold from the earths crust?
It is very unreactive, so it will not be bonded with other elements
136
How do most metals exist?
As compounds in rocks
137
What is an ore?
When there is enough metal compound in the rock to be worth extracting
138
When can metals be extracted by reduction with carbon?
When they are less reactive than carbon
139
What metals are less reactive than carbon?
Zinc, iron, tin, lead, copper, silver, and gold
140
When do we use electrolysis to separate metals?
When they are more reactive than carbon
141
Define oxidation
When a substance gains oxygen in a reaction
142
Define reduction
When a substance loses oxygen in a reaction
143
What is a displacement reaction?
Reaction where a more reactive element takes the place of a less reactive element in a compound
144
What does a metals reactivity depend on?
How readily forms an ion
145
What are acids?
Compounds that when dissolved in water release H+ ions.
146
What are the three main acids?
Sulphuric acid (H2SO4), nitric acid (HNO3), hydrochloric acid (HCl)
147
What are alkalis?
Compounds that when dissolved in water release OH- ions
148
What is the pH scale?
A scale to measure the acidity and alkalinity running from 1 to 14
149
When is an aqueous solution acidic?
With a pH below 7
150
When is an aqueous solution alkaline?
With a pH above 7
151
When is an aqueous solution neutral?
With a pH of 7
152
What does the pH scale tell us?
How many H+ ions there are in a solution. The more H+ ions that are present, the lower the pH.
153
What is an indicator?
Something used to show if something is acidic or an alkali
154
What is universal indicator?
An indicator to tell us an approximate pH of a solution through use of colour
155
What is an electronic pH probe?
Approve used to give the exact pH of a solution
156
Name three strong acids
Sulphuric acid, nitric acid and hydrochloric acid
157
What is meant by a strong acid?
An acid that, when dissolved in water, every molecule splits up into ions. This means they are completely ionised.
158
Name three weak acids
Ethanoic acid, citric acid and carbonic acid
159
What is meant by a weak acid?
Only a percentage of the molecules split up into ions when dissolved in water. This means they are partially ionised.
160
Describe the trend in concentration and pH
For a given concentration, the stronger the acid, the lower the pH
161
What does concentration tell us with us with acids?
Concentration tells us how much of a substance that is dissolved in water
162
What is meant by a more concentrated acid?
There is lots of acid in a small volume of water
163
What is meant by a dilute acid?
There is little acid in a large volume of water
164
What is meant by Dilute strong acid?
There are a few acid ions. They are completely ionised.
165
What is meant by concentrated strong acid?
There are lots of acid ions, they are all completely ionised
166
What is meant by a dilute weak acid?
There are a few acid ions and they are partially ionised
167
What is meant by concentrated weak acid?
There are lots of acid ions and they are partially ionised
168
When is a salt formed?
When acids react with metals or metal compounds
169
What is a salt?
A compound where the hydrogen from an acid has been replaced by a metal
170
What salt is formed from hydrochloric acid?
A metal chloride
171
What salt is formed from sulphuric acid
Metal sulphate
172
What metal is formed from nitric acid?
Metal nitrate
173
What are the products of a reaction between an acid and a metal?
A salt and hydrogen gas
174
What are the products of reactions with of acid and metal hydroxides?
Salt and water
175
What are the products of a reaction of acid and a metal oxide?
Salt and water
176
What are the products of a reaction with acid and a metal carbonate?
Salt, water and carbon dioxide
177
What type of reaction is the reaction between an acid and metal?
A redox reaction. The metal loses electrons so it is oxidised. Hydrogen gains an electron so it is reduced.
178
What devices do in a neutralisation reaction?
Bases neutralise acids to form water
179
What is formed when a metal hydroxides dissolve in water?
Alkaline solutions which are called alkalis
180
What is a base?
A metal oxide or metal hydroxide that doesn’t dissolve in water
181
What is the experimental method of crystallisation?
* choose the correct acid and base to produce the salt
* put some of the dilute acid into a flask and heat gently with a Bunsen
* add a small amount of the base and stir
* keep adding the base until no more reacts (The base is now in excess)
* filter to remove the unreactive base
* add the remaining solution to an evaporating dish
* use a water bath to evaporate the water
* leave to crystallise
182
What is electrolysis?
The process of passing an electrical current through an electrolyte to separate the components
183
What is an electrolyte?
A liquid or solution that contains ions so can conduct electricity. This causes the ions to move to the electrodes, where they form pure elements.
184
How do you conduct electrolysis on solids?
Melt or dissolve them in water so the ions can move freely
185
In a molten compound, which electrode are the metal ions attracted to?
Cathode
186
In a molten compound, which electrode is the non-metal attracted to?
Anode
