C3 - Structure and Bonding Flashcards
1
Q
What is an alloy?
A
A mixture of two or more elements, at least one of which is a metal
2
Q
What is a Covalent bond?
A
the bond between two atoms that share one or more pairs of electrons
3
Q
What is covalent bonding?
A
the attraction between two atoms that share one or more pairs of electrons
4
Q
What is a delocalised electron?
A
bonding electron that is no longer associated with any one particular atom
5
Q
What is a dot and cross diagram?
A
a drawing to show only the arrangement of outer shell electrons of the atoms or ions in a substance
6
Q
What is a fullerene?
A
Carbon allotropes which exist in the form of large, hollow, spherical molecules in a cage-like strucuture. Based on hexagonal rings of carbon atoms
7
Q
What are gases?
A
substances that have no fixed shape or volume and can be compressed easily
8
Q
What is a giant covalent structure?
A
a huge 3D network of covalently bonded atoms
9
Q
What is a giant lattice?
A
a huge 3D network of atoms or ions
10
Q
What is a giant structure?
A
a huge 3D network of atoms or ions
11
Q
What are intermolecular forces?
A
the attraction between the individual molecules in a covalently bonded substance
12
Q
What is an ionic bond?
A
the electrostatic force of attraction between positively and negatively charged ions
13
Q
What is a liquid?
A
substances that have a fixed volume, but they can flow and change their shape
14
Q
What is nanoscience
A
the study of very tiny particles or structures between 1 and 100 nanometres in size
15
Q
What is particle theory?
A
a theory that explains the properties of solids, liquids and gases based on the fact that all matter is made from tiny particles. It describes the movement of particles and the distance between them
16
Q
What is a polymer?
A
a substance made from very large molecules made up of many repeating units
17
Q
What are solids?
A
substances that have a fixed shape and volume that cannot be compressed. the particles cannot move, only vibrate
18
Q
What is states of matter?
A
the forms in which matter can exist. A substance can be solid, liquid or gas
19
Q
In melting and boiling the energy is transferred from ……… to the …………
A
In melting and boiling the energy is transferred from the surroundings to the substance
20
Q
In freezing and condensing the energy is transferred from ……… to the …………
A
In freezing and condensing the energy is transferred from substance to the surroundings
21
Q
What are the limitations of particle theory?
A
The particle model is limited as it assumes particles are solid spheres with no forces between them, however particles can be atoms, molecules or ions. They can vary in size. They can contain many atoms and they are not solid or spherical.
22
Q
What is covalent bonding?
A
Covalent bonding is the electrostatic attraction between a shared pair of electrons and the nuclei of 2 atoms. (When 2 atoms share a pair of electrons)
23
Q
What is Ionic bonding?
A
Ionic bonding is the electrostatic attraction between oppositely charged ions
24
Q
What type of elements form positive ions?
A
metals
25
What type of elements form negative ions?
non-metals
26
What do dot and cross diagrams show?
the electron transfer during the formation of an ionic compound
27
What is the arrangement of ionic bonding?
a giant lattice structure
28
What is the conductivity of ionic bonds as a solid?
they do not conduct
29
What is the conductivity of ionic bonds as a liquid?
they can conduct
30
What is an ion?
A charged atom formed by the loss or gain of electrons
31
Why do atoms lose or gain electrons to form ions?
To obtain a full outer shell of electrons
32
What are negative ions called?
Anions
33
What are positive ions called?
Cations
34
What is the formula of Lithium?
Li¹+
35
What is the formula of Potassium?
K¹+
36
What is the formula of Silver?
Ag¹+
37
What is the formula of Magnesium?
Mg²+
38
What is the formula of Copper?
Cu²+
39
What is the formula of Aluminium?
Al³+
40
What is the formula of Chromium?
Cr³+
41
What is the formula of Ammonium?
NH₄¹+
42
What is the formula of Fluoride?
F¹-
43
What is the formula of Bromide?
Br¹-
44
What is the formula of Hydroxide?
OH¹-
45
What is the formula of Chloride?
Cl¹-
46
What is the formula of Nitrate?
NO₃¹-
47
What is the formula of Sulfate?
SO₄²-
48
What is the formula of Carbonate?
CO₃²-
49
What is the structure of an ionic compound?
Giant Lattice
50
What state are ionic compounds at room temperature?
Solid
51
Why do ionic compounds have a high melting point?
Lots of energy is required to break every ionic bond
52
In what state do ionic compounds conduct?
Liquid/aqueous solution
53
Why do ionic compounds only conduct as a liquid or an aqueous solution?
Ionic compounds contain charged particles but the particles are not free to move as a solid as they are fixed in a lattice, when molten these particles can move freely and can conduct
54
What does the formula Na₂S mean?
the ionic compound Sodium Sulphate has Sodium ions and Sulphur ions in the ratio 2:1
55
What is a molecule?
A substance made up of non-metal atoms joined by covalent bonds
56
When are covalent bonds formed?
When atoms share a pair of electrons
57
What are the advantages of using dot and cross models to represent molecules?
They are useful for illustrating sharing/transfer of electrons. They indicate which atoms the shared electrons have come from.
58
What are the disadvantages of using dot and cross models to represent molecules?
They fail to illustrate the 3d arrangement of the atoms and the electron shells. They do not indicate the relative size of atoms and subatomic particles.
59
What are the advantages of using 3d "stick" representation of molecules?
They are useful for illustrating the arrangements of atoms in 3d space. They are very useful for visualising the shape of the molecule
60
What are the disadvantages of using 2d "stick" representation of molecules?
They fail to indicate the movement of electrons. The atoms are placed far apart from each other, which in reality is not the case as the gaps between atoms are much smaller.
61
ions are formed when what type of elements react?
metals and non-metals
62
What type of elements lose electrons?
metals
63
What type of elements gain electrons?
non-metals
64
Explain what the formula Al₂O₃ tells us about aluminium oxide?
The ionic compound of Aluminium Oxide contains Aluminium ions and Oxygen ions in the ratio 2:3
65
Aluminium oxide has a very high melting point while carbon dioxide has a very low melting point. Explain this difference.
Aluminium oxide is ionically bonded and therefore has many strong ionic bonds between each ion. For it to melt every bond needs to be broken and therefore a lot of energy is required whereas Carbon Dioxide has simple molecular bonding and therefore has a low melting point as it has weak intermolecular forces between each molecule which do not require much energy to break.
66
Carbon dioxide does not conduct electricity in any state whereas aluminium oxide will conduct electricity when it is molten. explain this difference.
For a substance to conduct it needs to have mobile charged particles. Carbon dioxide is covalently bonded and therefore does not have any charged particles. That means that the carbon dioxide cannot conduct in any state. Aluminium oxide is ionically bonded which means that it does have charged particles. When it is in a solid state it does not have "mobile particles" as it is fixed in a lattice and therefore cannot conduct, however when molten it does have charged particles that are free and can therefore conduct.
67
Explain why ammonia has a low melting point.
Ammonia has a simple molecular structure, this means that it has weak intermolecular forces and very little force is required to break these bonds.
68
Explain why diamond is hard but graphite is soft.
Diamond has a giant covalent lattice and each carbon atom is bonded to 4 other carbon atoms. On the other hand, graphite is formed in layers and each carbon atom is bonded to only 3 other carbon atoms. This causes graphite to be soft as the layers of graphene can slide off of each other
69
Why does graphite conduct but diamond cannot?
For a substance to conduct it needs to have mobile charged particles. Diamond is covalently bonded and it does not have any delocalised electrons, this means that diamond does not have any mobile charged particles and cannot conduct. Whereas graphite is formed in layers and each carbon atom is bonded to only 3 other carbon atoms. This causes there to be an extra unbonded electron, thus forming a sea of delocalised electrons. These delocalised electrons are free to move and they are charged. This means that graphite can conduct.
70
What do dots/crosses represent in a dot and cross diagram?
electrons
71
What is the structure type of Diamond?
Giant Covalent
72
What is the structure type of Graphite?
Giant Covalent
73
What is the structure type of Buckminsterfullerene?
Simple Molecular
74
What is the structure type of Graphene?
Giant Covalent
75
What is the formula of Diamond?
C
76
What is the formula of Graphite?
C
77
What is the formula of Buckminsterfullerene?
C₆₀
78
What is the formula of Graphene?
C
79
What is the Number of covalent bonds for each C atom for diamond
4
80
What is the Number of covalent bonds for each C atom for graphite
3
81
What is the Number of covalent bonds for each C atom for Buckminsterfullerene
3
82
What is the Number of covalent bonds for each C atom for Graphene
3
83
What is the melting/boiling point for diamond?
very high
84
What is the melting/boiling point for graphite?
very high
85
What is the melting/boiling point for Buckminsterfullerene?
not very high
86
What is the melting/boiling point for Graphene?
very high
87
What is the reason for the melting/boiling point for diamond?
Need to break many strong covalent bonds
88
What is the reason for the melting/boiling point for graphite?
Need to break many strong covalent bonds
89
What is the reason for the melting/boiling point for Buckminsterfullerene?
Only need to break relatively weak intermolecular forces
90
What is the reason for the melting/boiling point for Graphene?
Need to break many strong covalent bonds
91
What is the electrical conductivity of diamond?
insulator
92
What is the electrical conductivity of graphite?
conductor
93
What is the electrical conductivity of Buckminsterfullerene?
insulator
94
What is the electrical conductivity of Graphene?
conductor
95
What is the reason for the electrical conductivity of diamond?
has no delocalised electrons
96
What is the reason for the electrical conductivity of graphite?
has delocalised electrons
97
What is the reason for the electrical conductivity of Buckminsterfullerene?
Has delocalised electrons but they cannot move from 1 molecule to another
98
What is the reason for the electrical conductivity of graphene?
has delocalised electrons.
99
What is the strength of diamond?
very strong and hard
100
What is the strength of graphite?
soft and brittle
101
What is the strength of buckminsterfullerene?
soft and brittle
102
What is the strength of graphene?
extremely strong
103
What is the structure of graphite?
layers of graphene with weak forces between layers
104
What is the structure of Buckminsterfullerene?
a spherical molecule with the formula of C₆₀
105
What are nanotubes?
Thin tubes made of rolled up graphene, their length is much greater than their diameter
106
As particles decrease in size their surface area ............. in relation to their volume
As particles decrease in size their surface area Increases in relation to their volume
107
What is the formula for surface area to volume ratio?
Surface area to volume ratio = surface area / volume
108
What is the main industrial application of nanoparticles?
catalysts
109
Why are nanoparticles used as catalysts?
They have a high surface area : volume ratio
110
What are the main risks of nanoparticles?
The use of nanoparticles in science is in its early stages so there are still a lot of unknown factors and potential risks. In particular there is a lack of understanding on how they may affect health, particularly in the long term. Even a small amount of toxicity in a particular nanoparticle would be multiplied due to the high surface area to volume ratio. This coupled with the fact that they are not easily disposed of by the body are a cause for caution in the medical application of nanoparticles.
111
A cube has sides of 8nm. What is the surface area to volume ratio of the cube?
0.75 : 1
112
What is the electrical conductivity of an ionic compound as a liquid?
conducts
113
What is the electrical conductivity of a metallic substance as a liquid?
conducts
114
What is the electrical conductivity of a covalent substance as a liquid?
does not conduct
115
What is the electrical conductivity of an ionic compound as a solid?
does not conduct
116
What is the electrical conductivity of a metallic substance as a solid?
conducts
117
What is the electrical conductivity of a covalent substance as a solid?
does not conduct
118
What is the melting/boiling point of a simple molecular structure?
low
119
What is the electrical conductivity of a simple molecular structure?
Does not conduct
120
What is the strength of a simple molecular structure?
Brittle
121
What is the reason for the melting/boiling point of a simple molecular structure?
weak intermolecular forces
122
What is the reason for the electrical conductivity of a simple molecular structure?
They do not have any mobile charged particles
123
What is the reason for the strength of a simple molecular structure?
weak intermolecular forces
124
What is the formula for Silicon Dioxide?
SiO₂
125
What are the 3 giant covalent structures?
Diamond, Silicon Dioxide, Graphite
126
What is the melting point of diamond and silicon dioxide?
very high
127
What is the electrical conductivity of diamond and silicon dioxide?
does not conduct
128
What is the strength of diamond and silicon dioxide?
strong
129
What is the reason for the melting point of diamond and silicon dioxide?
MANY strong covalent bonds so lots of energy is required to break these bonds
130
What is the reason for the electrical conductivity of diamond and silicon dioxide?
No mobile charged particles
131
What is the reason for the strength of diamond and silicon dioxide?
Rigid arrangement of atoms held in place by covalent bonds
132
Why is graphite used as pencil lead?
the layers can slide off of each other and stay on the paper, they are also a different colour to the paper
133
What is the melting point of graphite
very high
134
What is the electrical conductivity of graphite
conducts
135
What is the strength of graphite
brittle
136
What is the reason for the melting point of graphite
need to break all strong covalent bonds
137
What is the reason for the electrical conductivity of graphite
they have delocalised electrons that are free to move between layers
138
What is the reason for the strength of graphite
weak forces between layers so layers can slide
139
What type of element are simple molecular substances made out of?
non-metals
140
What is a metallic structure?
A GIANT LATTICE, the outer shell of electrons is delocalised leaving a lattice of positive ions. These delocalised electrons attract and are attracted to the positive ions
141
What is a metallic bond?
The electrostatic force of attraction between positive ions and negative delocalised electrons
142
How many delocalised electrons will there be per atom in a group 1 metal?
1
143
How many delocalised electrons will there be per atom in a group 2 metal?
2
144
How many delocalised electrons will there be per atom in a group 3 metal?
3
145
Which group of metal elements will have the strongest metallic bond?
Group 3 metals as they have the most delocalised electrons, this means that the electrostatic force between the electrons and the ions is increased.
146
What is the melting/boiling point in metals?
high
147
What is the electrical conductivity in metals?
good
148
What is the thermal conductivity in metals?
good
149
What is the strength of metals?
strong
150
What is the malleability of metals?
good
151
What is the reason for the melting/boiling point in metals?
They have high melting points as they have many strong metallic bonds that need to be broken for them to melt/evaporate. This means that lots of energy is required to break all these bonds
152
What is the reason for the electrical conductivity in metals?
It has delocalised electrons that can move freely throughout the lattice structure
153
What is the reason for the thermal conductivity in metals?
It has delocalised electrons that can move freely throughout the lattice structure
154
What is the reason for the strength of metals?
It has many strong metallic bonds between each molecule that require a lot of energy to break
155
What is the reason for the malleability of metals?
The movement of the lattice does not cause the molecules to repel each other.
156
What is an alloy?
An alloy is a substance that is a mixture of different elements that contains at least 1 metal. The different sized atoms disrupt the regular arrangement of the metals
157
Why are alloys more useful than the pure metal?
By mixing different metals you can combine their useful properties and due to atoms of different sizes it distorts the regular arrangement. By mixing metals it makes them stronger, harder and could give them more resistance to corrosion.
158
What is the melting and boiling points of monatomic substances?
Very Low
159
What is the melting and boiling points of ionic substances?
high
160
What is the melting and boiling points of simple molecular substances?
low
161
What is the melting and boiling points of giant covalent substances?
very high
162
What is the melting and boiling points of metallic substances?
high
163
What is the conductivity as a solid of monatomic substances?
does not conduct
164
What is the conductivity as a solid of ionic substances?
Does not conduct
165
What is the conductivity as a solid of simple molecular substances?
does not conduct
166
What is the conductivity as a solid of giant covalent substances?
does not conduct
167
What is the conductivity as a solid of metallic substances?
conducts
168
What is the conductivity when melted of monatomic substances?
does not conduct
169
What is the conductivity when melted of ionic substances?
conducts
170
What is the conductivity when melted of simple molecular substances?
does not conduct
171
What is the conductivity when melted of giant covalent substances?
does not conduct
172
What is the conductivity when melted of metallic substances?
conducts
173
What is the solubility in water of monatomic substances?
insoluble
174
What is the solubility in water of ionic substances?
soluble (usually)
175
What is the solubility in water of simple molecular substances?
Insoluble (usually)
176
What is the solubility in water of giant covalent substances?
insoluble
177
What is the solubility in water of metallic substances?
insoluble
178
What is the conductivity of a solution of monatomic substances?
insoluble
179
What is the conductivity of a solution of ionic substances?
conducts
180
What is the conductivity of a solution of simple molecular substances?
insoluble (usually)
181
What is the conductivity of a solution of giant covalent substances?
insoluble
182
What is the conductivity of a solution of metallic substances?
insoluble
183
What is a fullerene?
a fullerene is a large spherical molecule made from carbon
184
What is a cylindrical fullerene called?
A nanotube
185
What size range does nanoscience deal with?
between 1 and 100nm
186
What is the empirical formula?
a formula giving the proportions of the elements present in a compound but not the actual numbers or arrangement of atoms.
187
What are intramolecular forces?
An intramolecular force is any force that binds together the atoms making up a molecule or compound
188
What is the difference between intermolecular forces and intramolecular forces
An intramolecular force is any force that binds together the atoms making up a molecule or compound, not to be confused with intermolecular forces, which are the forces present between molecules
189
What is an ion of oxygen called?
Oxide
190
Why is buckminsterfullerene a good lubricant?
In buckminsterfullerene the molecules are spherical so the molecules will roll over each other
191
What are the 3 types of intramolecular forces?
* Ionic
* Covalent
* Metallic
192
What are the 5 different structure types of a substance?
* Giant Covalent
* Ionic
* Metallic
* Molecular
* Monatomic
193
What are the 5 different structure types of a substance?
* Giant Covalent
* Ionic
* Metallic
* Molecular
* Monatomic
194
Where do you draw the electrons in a dot and cross diagram for covalent bonds?
In the gap between the 2 electron shell
