Bonding, Structure and Properties of metals Flashcards
1
Q
What are ions?
A
They are charged particles which can be single atoms ( CL-) or groups of atoms (N0 3-)
2
Q
When atoms lose or gain electrons what are they trying to achieve?
A
They are trying to achieve a full outer shell like a noble gas as atoms with full other shells are very stable.
3
Q
How do metals form ions?
A
They lose electrons into their outer shell to form positive.
4
Q
How do non-metals form ions?
A
They gain electrons into their outer shell to form negative ions.
5
Q
The number of electrons lost or gained is the same as what?
A
It is the same as the charge on the ion. e.g. if 2 electrons are lost the charge is 2+
6
Q
What groups on the periodic table are likely to form ions?
A
Group 1 and 2 and 6 and 7
7
Q
What ions do Group 1 and 2 metals form?
A
they lose electrons to form positive ions.
8
Q
What ions do Group 6 and 7 non-metals form?
A
they gain electrons to form negative ions.
9
Q
What is a chemical bond?
A
it is an electrostatic attraction between a positive and a negative ion.
10
Q
What is Ionic bonding?
A
It is an electrostatic attraction between oppositely charged ions. (when a metal and a non-metal react)
11
Q
What happens when Lithium reacts with fluorine?
A
The lithium loses its outer electron and the fluorine atom gains it, now both the lithium atom and fluorine atom have a full outer energy level with ions.
12
Q
Describe what happens when Sodium reacts with Chlorine (4 marks)
A
One electron passes from the sodium atom to the chlorine atom, both atoms achieve a full outer energy level.
13
Q
How does a sodium atom turn into a sodium ion?
A
It loses one electron and gains a charge of 1+
14
Q
Explain why the chloride ion has a negative charge.
A
one more electron than protons
15
Q
Chloride ions are strongly attracted to sodium ions in sodium chloride. Explain why.
A
Because oppositely charged ions attract each other
16
Q
All group 7 elements can produce ions.
What is the charge on the ions produced by group 7 elements?
A
-1
17
Q
Many ionic compounds from what ?
A
Crystals
18
Q
What type of structures do ionic compounds form?
A
They form giant structures called giant ionic lattice where every positive ion is surrounded by negative ions.
19
Q
What do Giant ionic lattices have?
A
Very strong forces of attraction between positive and negative ions, which is called electrostatic forces.
20
Q
What do the electrostatic forces do in giant ionic lattices?
A
They hold the positive and negative ions in place.
21
Q
What are electrostatic bonds called in a giant ionic lattice?
A
Ionic bonds, attracting in all directions.
22
Q
Are giant ionic lattices 2D or 3D?
A
3D
23
Q
Give 2 properties of Ionic Compounds?
A
1) Ionic compounds have very high melting and boiling points.
2) Ionic compounds cannot conduct electricity when they are solids.
3) Ionic compounds can conduct electricity wen they are melted or dissolved in water.
24
Q
Why do ionic compounds have very high melting and boiling points?
A
Because the strong electrostatic forces require a great deal of heat energy to break the forces.
25
Why can Ionic compounds not conduct electricity?
Because the ions cannot move. They are locked in place by the strong electrostatic forces of attraction.
26
Why can ionic compounds conduct electricity when melted or dissolved in water?
Because the ions can now move and carry the charge.
27
Explain why the ions in this lattice stay in place
Sodium ions have a (single) positive charge and chloride ions have a (single) negative charge.
Ions with opposite charge are attracted (to each other) .
(Positive and negative) ions are arranged alternatively (in each direction)
28
On a dot and cross diagram metals are drawn with what?
Cross
29
On a dot and cross diagram non- metals are drawn with what?
Dots
30
What is covalent bonding?
When non-metal atoms bond together which share pairs of electrons
31
What does H2 tell us?
There are two hydrogen atoms bonded together
32
What happens when two hydrogen atoms react together?
Now both hydrogen atoms have 2 electrons meaning they have a full outer energy level, just like a group 0 noble gas. By sharing a pair of electrons the atoms have formed a single covalent bond.
33
What does a energy levels diagram show?
shows the energy levels and the covalent bond.
34
What is a dot and cross diagram?
it only shows electrons not the energy levels
35
What does a stick diagram show?
it shows what type covalent bond it is (shared paired of electrons)
36
What is the stick diagram for oxygen?
0=0
37
What is the stick diagram for Nitrogen?
N (triple bond)N
38
Covalent bonds are usually what?
simple small structures
39
What are the two properties of covalent bonds?
They have low melting and boiling points
| 2) Small covalent molecules do not conduct electricity
40
Because small covalent molecules have low melting and boiling points what does it mean its state is at room temperature?
Gases or liquids at room temperature, this is because they all boil at temperatures below room temperature.
41
Explain why small covalent molecules have low melting and boiling points?
The weak intermolecular(between molecules) forces between the molecules do not require a lot of energy to break.
42
Covalent bonds have what between atoms?
They have strong covalent bonds between atoms
43
Using hydrogen as an example, explain why small covalent molecules have low melting and boiling points?
Hydrogen molecules in liquid forms is at very cold temperatures, as we increase the temperature the vibration of molecules increase, at a certain point, this vibration is Strong enough to break the weak intermolecular forces, holding the molecules to each other, at this point the molecules turns into a gas (boil).
44
What are alkanes?
Small covalent molecules
45
Why do alkanes boiling point increase as they get larger?
The intermolecular forces increase which requires more energy to break.
46
Why don't small covalent molecules conduct electricity?
This is because the molecules do not have an overall electrical charge.
47
One of the gases present in the atmosphere is water vapor. Describe the bonding in this compound. (You must include electronic structures in your explanation.)
[4 marks]
Outer electronic structure of oxygen - has 6 electrons in outer shell. Outer electronic structure of hydrogen - has one electron two shared pairs of electrons (as covalent bond) outer electronic structure of compound correct or each atom now has a full outer shell/noble gas electron structure.
48
What are polymers?
they are made by joining thousands of repeating moclucles called monomers.
49
What are monomers?
Joint up molecules to form monomers.
50
Monomers are usually what?
usually alkene molecules such as ethene, they have a double carbon to carbon bond.
51
Polymers contain what?
contain single carbon to carbon covalent bonds.
52
All the atoms in a polymer are joined up by what?
Strong covalent bonds.
53
What is the problem of drawing polymers?
Some can be long polymers as there are lots of atoms of covalent bonds to draw
54
What short hand method do scientists use to draw polymers?
Repeating units.
55
What 3 things do repeating units show?
1) they show the single carbon to cabon bond
2) The covalent bonds have to extend out of the bracket.
3) The letter n shows us that the polymer contains a very large number of repeating units joined together.
56
What is the molecular formula for poly (ethene)?
C2H4)n
57
Name 2 properties of Polymers.
1) Most polymers are solid at room temperature
| 2) Polymers have a high melting point.
58
Why are polymers solid at room temperature?
Because the strong forces of attraction between polymer molecules are relatively strong
59
Why do polymers have a high melting point?
The intermolecular forces between polymer molecules are relatively strong, so it requires a great deal of energy to break the bonds.
60
Giant molecular molecules are always what at room temperature?
Solids at room temperature because they have millions of strong covalent bonds, meaning they have high melting and boiling points.
61
Diamond is an example of what?
A giant covalent bond
62
What is diamond formed from?
The element carbon
63
In diamond for each carbon atoms how many covalent bonds does it form to other carbon atoms?
In diamond each carbon atom forms 4 covalent bonds to 4 other carbon atoms.
64
What are two properties of Diamonds?
1) They have high melting and boiling points
| 2) They cannot conduct electricity
65
Why do diamonds have high melting and boiling points?
they have huge amounts of carbon atoms joined together by strong covalent bonds which require a lot heat energy to break the bonds.
66
Why cant diamond conduct electricity?
There are no free electrons to carry electrical charges.
67
Predict with reasoning whether diamond or polythene has a higher melting point?
To melt diamond you have to break the covalent bonds between the atoms which are very strong but to melt poly(ethene) you only have to break the weaker intermolecular forces which needs less energy, so diamond has a higher melting point.
68
Silicon dioxide is used for what?
Sand is made from silicon dioxide.
69
What elements is silicon dioxide contain?
Silicon and oxygen covalently bonded together.
70
Silicon dioxide is example of what?
A giant covalent molecule which contains a huge number of covalent bonds.
71
Name a property of Silicon dioxide?
It has a very high melting and boiling point.
72
Why does silicon dioxide have a high melting and boiling point?
This is because it has a huge number of strong covalent bonds which requires a great deal of energy to break it down.
73
Graphite is also an example of what?
A giant covalent structure
74
Graphite is a form of what?
Carbon
75
Each carbon atom of graphite forms how many covalent bonds?
3 covalent bonds, the carbon atoms form hexagonal rings.
76
What are 3 properties of covalent bonds?
1) Graphite has a high melting and boiling point
2) Graphite is slippery and soft
3) Graphite is an excellent conductor of both electricity and of heat.
77
Why does Graphite have a high melting and boiling points?
Because graphite has many strong covalent bonds it takes a great deal of energy to break these so graphite has a high melting and boiling point.
78
Why is graphite slippery and soft?
The graphite is in hexagonal rings, which have no covalent bonds between the layers so they can slide.
79
Why is Graphite is an excellent conductor of both electricity and of heat.
As we said each carbon atom forms 3 covalent bonds to 3 other carbon atom, meaning that each carbon atom has a single electron which is unbonded (there isn't a covalent bond). These electrons released from the carbon atom are called delocalised electrons, which can move, so therefore conduct heat and electricity.
80
Why isn't graphite a metal?
This is because graphite is based on the element carbon, so graphite is not a metal but has similar properties to metals such as good conductors of electricity as both graphite and metals have a delocalised electrons that cannot move.
81
What is Graphene?
It is a single layer of graphite and it is only one cell thick
82
Name 2 properties of graphene?
1) excellent conductor of electricity
| 2) Graphite is extremely strong and light
83
Why is Graphene an excellent conductor of electricity?
They have a delocalised electron just like graphite.
84
Because Graphene is extremely strong and light what can they be used for?
It can be added to composite materials to improve their strength without adding much weight.
85
Explain why Graphene can conduct electricity.
There are delocalised electrons. There is one free electron per atom meaning the free electrons can carry charge.
86
Diamond is much harder than graphite. Graphite can conduct electricity but diamond cannot.Explain why. (6 marks)
because layers of carbon atoms in graphite can either move or slide This is because there are only weak intermolecular forces between the layers
Diamond: in diamond each carbon atom is strongly (covalently) bonded to 4 others So no carbon atoms are able to move or slide Graphite: graphite has delocalised electrons which can carry current would charge through the structure, but diamonds do not have a delocalised electrons.
87
What is Fullerene?
Another type of carbon atom discovered very recently that form hollow tubes
88
How many rings of carbon do fullerenes usually have?
hexagonal rings but can also have 5 or 7 carbon atoms as well.
89
What was the first molecule of fullerene to be discovered?
Bucksiminster fullerene with 60 carbon atoms arranged in a hollow sphere
90
What are 3 uses of fullerenes?
1) they can be used for Pharmaceutical delivery as they are unreactive
2) Lubricants
3) Catalysts
91
What can fullerenes also form into?
Carbon nano-tubes (tiny carbon cylinders)
92
What are 3 properties of Fullerenes
1) Very high tensile strength (can be stretched without breaking)
2) Carbon nano-tubes are often excellent conductors of electricity
3) Used to reinforce equipment such as tennis rackets.
93
Nano-tubes are very strong and so could be used to make objects like tennis rackets.Explain why nano-tubes are strong.
Because graphene has a giant or lattice structure
Graphene has a covalent structure or covalent bonds between the atoms . The covalent bonds are very strong. A lot of energy is required to break the covalent bonds.
94
Metals consist of what?
A giant structure of atoms arranged in regular layers.
95
In a metal the elements in the outer energy level are what?
Delocalised electrons, the outer electron isn't attached to any individual atom, so there free to move.
96
Because each metal ion has lost its outer electrons we now refer to them as what?
Metal ions but this isn't ionic bonding
97
What is the key feature in bonding between metals?
We have a strong electrostatic attraction between the sea of delocalised negative electrons and positive metal ions.
98
What is a metallic bond?
the electrostatic attraction in metals between positive and negative objects, in which metallic bonds are strong.
99
Give 3 properties of metals?
1) High melting and boiling points
2) Excellent conductors of heat and electricity
3) Malleable
100
Why do metals have high melting and boiling points?
because it requires a great deal of energy to break the strong metallic bonds.
101
Why are metals great conductors of heat and electricity?
1) Because the delocalised electrons can move and because electrons are charged these moving electrons can carry an electric current.
2) The moving electrons can carry thermal (heat) energy which allows metals to conduct electricity.
102
Why are metals malleable (bent and shaped)?
this is because the layers of atoms are able to slide over each other.
103
What is an Alloy?
it is a mixture of metals
104
Why are alloys harder than pure metals?
The different sizes of atoms distorts the layers, making it very difficult for them to slide over each other.
105
Describe a solid?
They have strong forces of attraction between particles, which holds them closer together in a fixed position to form a very regular lattice arrangement
2) Particles don't move from their positions, so all solids keep a definite shape and volume
3) The particles vibrate about their conditions
106
Describe a Liquid?
1) Weak forces of attraction between particles, they're randomly arranged and free to move past each other, but tend to stick closely together
2) Liquids have a definite volume but don't keep their shape, they will flow to bottom of container.
3) the particles are constantly moving with random motion. the hotter the liquid the faster they move.
107
Describe a Gas?
The forces of attraction are very weak, they are free to move and far apart, the particle gas travels in straight lines.
2) Gases don't keep their definite shape or volume and will always fill container
3) The particles are constantly moving in random motion, pressure increases as particles get hotter.
108
What is melting point of water?
0'C
109
Describe melting?
This is when a solid turns into a liquid. This happens at the melting point of water 0'C. When a solid metal the particles start to gain energy from surroundings are start to vibrate more and more until the particles can start to move past each other.
110
Describe freezing?
This is when a liquid turns into a gas. This happens at the melting point of water. The particles lose energy when they cool down, they start to move less and less, untill they remain fixed in place vibrating only. That's when they are a solid.
111
Describe boiling?
This is when a liquid turns into a gas at its boiling point 100'C the liquid particles that were close together and are moving slowly past each other gain more and more energy, until some of the particles escape, eventually all the particles will have enough energy that they can break away from each other and start to move randomly in all directions.
112
Describe condensation?
This is when gases turn into liquid, this happens at the boiling point of 100'C. The gas particles have lots of energy, but as they lose energy, they start to lose less and less until none of the particles have enough energy to move away from each other and all stay close to each other.
113
Describe subliming?
This is when a solid changes straight into a gas without going through the liquid phase. In a solid the particles are really close together and cannot move around, as we give them more and more energy by heating it up the particles gain energy but because they are subliming they don't turn into liquids they turn straight into a gas as the particles have so much energy.
114
What are limitations to the particle model?
1) Particles aren't solid or inelastic and they aren't solid spheres, there atoms ions or molecules.
2) the model doesn't show the forces between the particles, so there is no way of knowing how strong they are.
115
If the temperature's below the melting point of a substance what state will it be?
A solid
116
If the temperature's above the melting point of a substance what state will it be?
A gas
117
If the temperature's between the two points what state will it be?
A liquid
118
```
Ethanol melts at -114'C and boils at 78'C predict what state ethanol will be at
A) -150'C
b) 0'C
3) 25'C
4) 100'C
```
1) solid
2) Liquid
3) Liquid
4) gas
