C4 Flashcards
0
Q
Who was J.J. Thompson? (2 points)
A
- In late 1890s
* Discovered the electron
1
Q
Who was John Dalton? (2 points)
A
- Early 1800s proposed a theory of atoms
* Proposed that all atoms of the same element were the same
2
Q
Who was Ernest Rutherford? (2 points)
A
- In 1911
* Discovered the atom had a dense centre - nucleus
3
Q
Who was Niels Bohr? (2 points)
A
- In 1911
* Predicted that electrons occupy orbitals
4
Q
What has led to the current theory of atomic structure? (1 point)
A
• The work of John Dalton, J.J. Thompson, Ernest Rutherford and Niels Bohr
5
Q
Who were Geiger and Marsden? (2 points)
A
- Collected some unexpected results of atomic theory
* Led to the model of the atom being modified in order to explain them
6
Q
What is the structure of an atom? (1 point)
A
• Atom has a central nucleus surrounded by shells of negatively charged electrons
7
Q
What is the nucleus of an atom made up of? (1 point)
A
• Protons and neutrons
8
Q
What is the charge of an atom? (2 points)
A
- The nucleus is positively charged
* Atom has no overall charge
9
Q
Why does an atom have no overall charge? (2 points)
A
- Same number of (positive) protons and (negative) electrons
* Charges cancel each other out
10
Q
What is the approximate radius of an atom? (1 point)
A
• 1^-10m
11
Q
What is the approximate mass of an atom? (1 point)
A
• 10^-23g
12
Q
What is the relative charge of a proton? (1 point)
A
• +1
13
Q
What is the relative mass of a proton? (1 point)
A
• 1
14
Q
What is the relative charge of a neutron? (1 point)
A
• 0
15
Q
What is the relative mass of a neutron? (1 point)
A
• 1
16
Q
What is the relative charge of an electron? (1 point)
A
• -1
17
Q
What is the relative mass of an electron? (1 point)
A
• 0.0005 (zero)
18
Q
What is an element? (2 points)
A
- Made of 1 type of atom
* Can’t be chemically broken down
19
Q
How many naturally occuring elements are there? (1 point)
A
• Over 100
20
Q
What is a compound? (1 point)
A
• A substance made of 2 or more elements that are chemically combined
21
Q
How can you identify the elements in a compound? (1 point)
A
• From its formula using the periodic table
22
Q
What does the compound Sodium Chloride (NaCl) contain? (2 points)
A
- The elements Sodium (Na)
* And Chlorine (Cl)
23
Q
What does the compound Potassium Nitrate (KNO3) contain? (3 points)
A
- The elements Potassium (K)
- Nitrogen (N)
- Oxygen (O)
24
What is the Mass Number? (1 point)
• The total number of protons and neutrons in an atom
25
What is the Atomic Number? (1 point)
• The proton number
26
How are the elements in the periodic table arranged? (1 point)
• In increasing atomic number
27
What can you use the periodic table to do? (2 points)
* Find an element from its atomic number
| * The atomic number of an element
28
What is the group number? (1 point)
• The same as the number of electrons in the outer shell of an element's atom
29
What is the period number? (1 point)
• The same as the number of occupied shells (shells that contain electrons) that an element's atom has
30
What is an isotope? (1 point)
• Atoms of the same element that have the same atomic number but different mass number
31
What does each isotope have? (1 point)
• The same number of protons and electrons, but different number of neutrons
32
What is electron configuration? (1 point)
• Tells you how the electrons are arranged around the nucleus in shells (energy levels)
33
How many electrons can the first shell of an atom hold? (1 point)
• Maximum of 2
34
How many electrons can the shells other than the inside shell hold? (1 point)
• Maximum of 8
35
What is an ion? (1 point)
• A charged atom or group of atoms
36
What is a positive ion? (2 points)
* An atom or group of atoms that have lost one or more electrons
* E.G. Losing 2 electrons makes a 2+ ion
37
What is a negative ion? (2 points)
* An atom or group of atoms have gained 1 or more electrons
| * E.G. gaining 2 electrons makes a 2- ion
38
What are the 3 things that happen in ionic bonding? (3 points)
* The metal atom loses all outer-shell electrons to become a positive ion
* The non-metal atom gains electrons to fill its outer shell (become a stable octet) to become a negative ion
* The positive and negative ions are attracted - called an ionic bond
39
What is ionic bonding? (2 points)
* Type of chemical bond that involves a metal and a nonmetal ion through electrostatic attraction
* In short, it is a bond formed by the attraction between two oppositely charged ions
40
What are 2 examples of ionically bonded compounds? (2 points)
* Sodium Chloride
| * Magnesium Oxide
41
What are 4 properties of ionically bonded compounds? (4 points)
* High melting points
* Don't conduct electricity when solid
* Dissolve in water
* Can conduct electricity when IN SOLUTION or when MOLTEN
52
What are 3 elements in the second period of the periodic table? (3 points)
* Lithium (Li)
* Carbon (C)
* Neon (Ne)
53
What does the period of an element relate to? (1 point)
• The number of occupied electron shells
54
If an element's electronic structure is 2.8.6 (sulfur), what is it's position in the periodic table? (2 points)
* 3 electron shells = third period
| * 6 electrons in outer shell = group 6
55
What are the 3 types of bonding? (3 points)
* Ionic bonding = metals and non-metals
* Covalent bonding = non-metals
* Metallic bonding = metals only
56
What is covalent bonding? (1 point)
• Non-metals combine by sharing pairs of electrons
57
What are 2 examples of covalently bonded molecules? (2 points)
* Water
| * Carbon dioxide
58
What does water (H2O) contain and what are its 3 properties? (4 points)
* Contains hydrogen and oxygen atoms
* Liquid at room temperature
* Low melting point
* Doesn't conduct electricity
59
What does Carbon dioxide (CO2) contain and what are its 3 properties? (4 points)
* Contains carbon and oxygen atoms
* Gas at room temperature
* Low melting point
* Doesn't conduct electricity
60
What is one molecule of water made up of? (1 point)
• 1 oxygen atom, 2 hydrogen atoms
61
What is one molecule of carbon dioxide made up of? (1 point)
• 1 carbon atom, 2 oxygen atoms
62
What are 2 examples of simple covalently bonded molecules? (2 points)
* Water
| * Carbon dioxide
63
What do simple covalently bonded molecules have? (1 point)
• Weak intermolecular forces of attraction between molecules
64
Why do simple covalently bonded molecules have low melting points? (1 point)
• Because they have weak intermolecular forces of attraction between molecules
65
Why don't simple covalently bonded molecules conduct electricity? (1 point)
• There aren't any free electrons
66
Who was Dobereiner? (3 points)
* First to suggest Law of Triads, where he grouped the elements into sets of 3 with similar properties
* Middle element would have the average mass of other 2 elements
* But - not all elements were known, pattern did not work for every known element
67
Who was John Newlands? (2 points)
* First scientist to make a table of elements, called the Law of Octaves, where every 8th element behaved the same
* But - he included some compounds as he believed them to be elements
68
Who was Mendeleev? (4 points)
* The author of the modern periodic table
* He left gaps in his table for the unknown elements and made predictions about their properties
* His predictions were later proved correct
* Also, investigations on atomic structure agreed with his ideas
69
Where are the Alkali metals found in the periodic table? (1 point)
• Group 1
70
What are the first 3 elements in the Alkali metals group? (3 points)
* Lithium
* Sodium
* Potassium
71
How do the alkali metals (group 1) have similar properties? (1 point)
• They have 1 electron in their outer shell
72
Why are alkali metals stored under oil? (2 points)
* They react with air
| * React vigorously with water
73
What do alkali metals with water to produce? (2 points)
* Hydrogen
| * A hydroxide
74
Why are alkali metals known as they are? (1 point)
• Alkali metal hydroxides are soluble and form alkaline solutions
75
Decribe how the alkali metals react more vigorously as you go down the group (3 points)
* Lithium reacts gently
* Sodium reacts more aggressively than sodium
* Potassium reacts more aggressively than sodium - it melts and burns with a lilac flame
76
Give the word equation of lithium + water (1 point)
• Lithium + water ---> Lithium hydroxide + hydrogen
77
Give the symbol equation of lithium + water (1 point)
• 2Li(s) + 2H2O(l) ---> 2LiOH(aq) + H2
78
Give the word equation for sodium + water (1 point)
• Sodium + water ---> Sodium hydroxide + hydrogen
79
Give the symbol equation for sodium + water (1 point)
• 2Na(s) + 2H2O(l) ---> 2NaOH(aq) + H2
80
Give the word equation for potassium + water (1 point)
• Potassium + water ---> Potassium hydroxide + hydrogen
81
Give the symbol equation for potassium + water (1 point)
• 2K(s) + 2H2O(l) ---> 2KOH(aq) + H2(g)
82
How can lithium, sodium and potassium compounds be recognised? (1 point)
• The colours they make im a flame test
99
What are the 5 non-metals in Group 7 called? (1 point)
• The Halogens
115
What do Sodium chloride and Magnesium oxide form? (1 point)
• Giant ionic lattices
116
What is in giant ionic lattices? (1 point)
• Positive and negative ions are strongly attracted to each other
117
What are 3 properties of giant ionic lattices? (3 points)
* High melting points due to strong attraction between oppositely charged ions
* Can conduct electricity when molten or in solution because charged ions are free to move about
* Don't conduct electricity ehen solid, as the ions are held in place and can't move
118
Why does magnesium oxide have a higher melting point than sodium chloride? (1 point)
• The ionic bonds are stronger and require more energy to be broken
119
What do ions with different charges combine to form? (1 point)
• Ionic compounds which have equal amounts of positive and negative charge
120
What is a vertical column of elements in the periodic table called? (1 point)
• A group
121
What are 3 elements in Group 1 of The Periodic Table? (3 points)
* Lithium (Li)
* Sodium (Na)
* Potassium (K)
122
What do elements in the same group have and why? (1 point)
• Similar chemical properties because they have the same number of electrons in their outer shell
123
What is the outer number of electrons the same as? (1 point)
• The group number
124
What is a horizontal row of elements in the periodic table called? (1 point)
• A period
125
What are the 3 steps taken in a flame test? (3 points)
* A piece of clean nichrome wire is dipped in water
* The wire is dipped in the solid compound (known as the sample), and then put into a Bunsen flame
* Each compound produces a different coloured flame
126
During the flame test, what colour does Lithium turn? (1 point)
• Red
127
During the flame test, what colour does Sodium turn? (1 point)
• Yellow
128
During the flame test, what colour does Potassium turn? (1 point)
• Lilac
129
What do alkali metals have in common? (2 points)
* Similar chemical properties
| * Similar physical properties
130
What element is Rubidium in Group 1? (1 point)
• 4th
131
Why are metals able to conduct electricity? (1 point)
Because the electrons flow freely through them, moving from atom to atom
132
Describe Rubidium's reaction with water (3 points)
* Very fast
* Exothermic (gives out energy)
* Violent (if carried out in glass beaker, it may shatter)
133
What happens to the Alkali metals as you do down group 1? (1 point)
• Their density increases (aside from potassium)
134
Which element has the greatest density, melting and boiling points of the group 1 alkali metals? (1 point)
• Caesium
135
Why do the alkali metals become more reactive as you go down the group? (1 point)
• The outer shell gets further away from the positive attraction of the nucleus, making it easier for an atom to lose an electron from its outer shell
136
What are the 3 equations for the formation of the Group 1 metal ions? (3 points)
* Li ---> Li^+ + e^-
* Na ---> Na^+ + e^-
* K ---> k^+ + e^-
137
Why do alkali metals have similar CHEMICAL properties? (2 points)
* As they react, each atom loses one electron from its outer shell
* So, a positive ion with stable electronic structure is made
138
What is oxidation? (1 point)
• The loss of electrons by an atom
139
In an ionic equation, if an electron has been lost, what reaction has taken place? (1 point)
• Oxidation
141
How do the Group 7 halogens have similar chemical properties? (1 point)
• They have 7 electrons in their outer shell
142
What are 4 examples of halogens? (4 points)
* Fluorine
* Chlorine
* Bromine
* Iodine
143
What are chlorine, bromine and iodine at room temperature? (3 points)
* Chlorine is a green gas
* Bromine is an orange liquid
* Iodine is a grey solid
144
What are 2 uses of the halogens? (2 points)
* Iodine = used as an antiseptic to sterilise wounds
| * Chlorine = used to sterilise water, to make pesticides and plastics
145
What do halogens react vigorously with, and what do they form? (2 points)
* React with alkali metals
| * Form metal halides
146
Give the word equation for the reaction of lithium and chlorine (1 point)
• Lithium + chloride ---> lithium chloride
147
Give the symbol equation for the reaction of lithium and chlorine (1 point)
2Li(s) + Cl2(g) ---> 2LiCl(s)
148
What happens as you go down the group 7? (1 point)
• The reactivity of the halogens decreases
149
What is the most reactive halogen? (1 point)
• Fluorine
150
What is the least reactive halogen? (1 point)
• Iodine
151
What will a more reactive halogen displace? (1 point)
• A less reactive halogen from an aqueous solution of its metal halide
152
What will chloride displace? (1 point)
• Bromides and iodides
153
What will bromine displace? (1 point)
• Iodides
154
If chlorine gas was passed through an aqueous polution of potassium bromide, what would be made in the displacement reaction? (1 point)
• Bromine and Potassium Chloride
155
What will fluorine displace? (1 point)
Fluorine is the most reactive element in Group 7, it will displace all of the other halogens from an aqueous solution of their metal halides
156
What is astatine? (1 point)
A semi-metallic, radioactive element and only very small amounts are found naturally. It's the least reactive of the halogens and, theoretically, it would be unable to displace any of the other halogens from an aqueous solution of their metal halides.
157
Why are the boiling and melting points plus the density of astatine estimated? (1 point)
Because astatine is very unstable and difficult to study
158
Why do the halogens have similar chemical properties? (1 point)
Because as they react, each atom gains one electron to form a negative ion with a stable electronic structure
159
Why are the halogens at the top of the group more reactive than those at the bottom? (1 point)
Because the outer shell is closer to the positive attraction of the nucleus - this makes it easier to gain an electron
160
What are the transition metals? (1 point)
A block of metallic elements, between Groups 2 and 3 of the periodic table
161
Give 6 examples of transition metals? (6 points)
- Iron (Fe)
- Copper (Cu)
- Platinum (Pt)
- Mercury (Hg)
- Chromium (Cr)
- Zinc (Zn)
162
Give 3 examples of how the transition metals' compounds are often coloured? (3 points)
- Copper compounds are blue
- Iron(II) compounds are light green
- Iron(III) compounds are orange-brown
163
Give 2 examples of how transition metals and their compounds are catalysts? (2 points)
- Iron is used in the Haber process
| - Nickel is used in the manufacture of margarine
164
What is thermal decomposition? (1 point)
A reaction where a substance is broken down into 2 or more substances by heating
165
What happens when transition metal carbonates are heated? (1 point)
A colour change happens. They decompose (break down) to form a metal oxide and carbon dioxide. The test for carbon dioxide is that it turns limewater milky.
166
What is precipitation? (1 point)
The reaction between solutions that makes an insoluble solid - known as a precipitate
167
Give 2 uses of transition metals? (2 points)
- Iron is used to make steel (which is used to make cars and bridges because its very strong)
- Copper is used to make electrical wiring because its a good conductor
168
Give 5 properties that make metals very useful materials? (5 points)
- They're lustrous (e.g. gold is used in jewellery)
- They're hard and have a high density (e.g. steel is used to make drill parts)
- They have high tensile strength (able to bear loads, e.g. steel is used to make bridge girders)
- They have high melting and boiling points (e.g. tungsten is used to make light-bulb filaments)
- They're good conductors of heat and electricity (e.g. copper is used to make both pans and wiring)
169
What is the structure of metals? (3 points)
- Metal atoms are packed very close together in a regular arrangement
- The atoms are held together by metallic bonds
- As the metal atoms pack together, they build a structure of crystals
170
Why do metals have high melting and boiling points? (1 point)
Because lots of energy is needed to break the strong metallic bonds
171
What are metal crystals made from? (1 point)
Closely packed positive metal ions in a 'sea' of delocalised electrons - the free movement of the electrons allows the metal to conduct electricity
172
What is metal held together by? (1 point)
Strong forces called metallic bonds, these are the electrostatic attractions between the metal ions and the delocalised electrons, so the metals have high melting and boiling points
173
What can some metals become at low temperatures? (1 point)
Superconductors - these have little, or no resistance to the flow of electricity
174
What is the low resistance of superconductors useful for? (3 points)
- Powerful electromagnets (e.g. inside medical scanners)
- Very fast electronic circuits (e.g. in a supercomputer)
- Power transmission that doesn't lose energy
175
What is the disadvantage of current superconductors? (1 point)
That they only work at temperatures below -200°C. This very low temperature is costly to maintain and impractical for large-scale uses. So, there is a need to develop superconductors that will work at room temperature (20°C).
176
What are the 4 main water sources in the UK? (4 points)
- Lakes
- Rivers
- Reservoirs
- Aquifers (wells and bore holes)
177
What does the chemical industry use water for? (3 points)
- As a solvent
- As a coolant
- As a raw material
178
What does The World Health Organisation estimate with regard to clean water? (2 points)
- Over 2 million people worldwide die per year from water-borne diseases
- Nearly 20% of the world's population doesn't have access to clean drinking water
179
What can untreated (raw) water contain? (4 points)
- Insoluble particles
- Pollutants
- Microorganisms
- Dissolved salts and minerals
180
Why isn't tap water pure? (1 point)
It contains soluble materials that aren't removed by the normal water treatment process, so extra care must be taken to remove them
181
How can pure water be obtained? (1 point)
It must be distilled, but this process uses a lot of energy and is expensive
182
Why is sea water distillation expensive? (1 point)
The equipment and energy needed to distill sea water is very expensive, the cost of making drinking water out of sea water is currently too high to make it a realistic option in the UK
183
Give 3 examples of pollutants in water supplies that can be very difficult to remove? (3 points)
- Nitrates from run-off fertilisers
- Lead compounds from old pipes in the plumbing
- Pesticides from spraying crops near to the water supply
184
Why is it important to conserve water? (1 point)
Because in some parts of Britain, the demand for water is higher than the supply
185
How are the dissolved ions from some salts easy to identify? (1 point)
As they will undergo precipitation reactions
186
When does a precipitation reaction occur? (1 point)
When an insoluble solid is made from mixing two solutions together
187
How can sulfates be detected in precipitation reactions? (1 point)
Using barium chloride - a white precipitate of barium sulfate forms
188
Give an example of how a sulfate is detected in precipitation reactions? (1 point)
Sodium sulfate + Barium chloride ---> Barium sulfate (white precipitate) + Sodium chloride
Na2SO4(aq) + BaCl2(aq) ---> BaSO4(s) + 2NaCl(aq)
189
What is used to detect halide ions? (1 point)
Silver nitrate solution
190
What are halides? (1 point)
The ions made by the Group 7 Halogens
191
Give 3 examples of how silver nitrate is used to detect halide ions? (3 points)
- Chlorides form a white precipitate
Sodium chloride + Silver nitrate ---> Silver chloride (white precipitate) + Sodium nitrate
NaCl(aq) + AgNO3(aq) ---> AgCl(g) + NaNO3(aq)
- Bromides form a cream precipitate
Sodium bromide + Silver nitrate ---> Silver bromide (cream precipitate + Sodium nitrate
NaBr(aq) + AgNO3(aq) ---> AgBr(s) + NaNO3(aq)
- Iodides form a pale yellow precipitate
Sodium iodide + Silver nitrate ---> Silver iodide (pale yellow precipitate) + Sodium nitrate
NaI(aq) + AgNO3(aq) ---> AgI(s) + NaNO3
