Structure And Bonding Flashcards
1
Q
What is a row called?
A
Period
2
Q
What is a column called?
A
Group
3
Q
What do atoms in the same group have the same number of?
A
Electrons in their outer shell
4
Q
What do atoms in the same group show similar of?
A
Chemical properties
5
Q
What does the atomic number tell us?
A
Number of protons
6
Q
What does the number of protons tell us?
A
Number of electrons
7
Q
What does the mass number tell us?
A
Number of protons + neutrons
8
Q
Number of neutrons =
A
Mass number - atomic number
9
Q
What do elements in the same period have the same of?
A
Number of shells
10
Q
Which number is the mass number?
A
The top one (always bigger)
11
Q
Which number is the atomic number?
A
The bottom one (always smaller)
12
Q
What tells us the electronic configuration?
A
Atomic number (bottom number, smaller number)
13
Q
What is a covalent bond?
A
The electrostatic attraction between a shared pair of electrons and nuclei of the to bonded atoms
14
Q
What does covalent bonding take place between?
A
Non-metal atoms
15
Q
When are atoms stable?
A
When they have a full outer shell of electrons
16
Q
Is covalent bonding sharing or transferring electrons?
A
Sharing
17
Q
Examples of simple molecules
A
Chlorine
Hydrogen
Nitrogen
Ammonia
Water
Methane
18
Q
What is a simple molecule?
A
A small group of atoms covalently bonded
19
Q
What are the atoms joined by (simple molecules)?
A
Strong covalent bonds
20
Q
What is between the individual molecules (simple molecules)?
A
Weak intermolecular forces
21
Q
What can covalent bonds be used to make?
A
Much larger structures such as polymers and giant covalent structures
22
Q
What happens when you heat iodine?
A
Sublime’s forming purple vapour
23
Q
What happens when you heat wax?
A
Melts into a colourless liquid
24
Q
What happens when you heat ice?
A
Melts into water
25
What happens when you heat sulphur?
Melts into an orange/yellow liquid
26
Do simple molecules have low or high melting/boiling points?
Low melting and boiling points
27
Why do simple molecules have low melting/boiling points?
The intermolecular forces are weak and so only require a small amount of energy to break them which means they’ll break at low temperatures
28
Do simple molecules conduct electricity?
No
29
Why don’t simple molecules conduct electricity?
The electrons are held in the shell (no free electrons) and cannot move
The molecules themselves have no electric charge
30
The more intermolecular forces a molecule has the …?
Stronger the overall attraction
31
What type of covalent bonds are the molecules in ice?
Strong
32
What type of intermolecular forces are between molecules in ice?
Weak
33
How much energy is needed to overcome the intermolecular forces in ice?
Small amount of energy is needed for the molecules to overcome the i.f and change into a liquid arrangement
34
Substances made from bigger, heavier molecules have …?
Stronger intermolecular forces than those made from smaller, lighter molecules
35
Why does carbon dioxide have a higher melting point than nitrogen?
It has more and bigger molecules - so stronger intermolecular forces
36
What is a giant covalent structure?
Single structures in which all the atoms are covalently bonded and held together in a single giant structure
37
How are giant covalent structures arranged?
Into regular repeating lattices
38
Are giant covalent structures strong or weak?
Very strong
39
Do giant covalent structures have low or high melting/boiling points?
High
40
Do giant covalent structures conduct electricity?
No, even when molten
(Except graphite)
41
What is an allotrope?
Different structural forms of the same element in the same physical state
42
What are 3 allotropes of carbon?
Diamond
Graphite
Fullerenes
43
What are diamonds?
Giant covalent structures
44
How many covalent bonds does each carbon have in a diamond?
4
45
What pattern is in a diamond?
Regular 3D pattern
46
Properties of diamonds
Hard
String
High melting point
47
Why is diamond hard?
Because of strong covalent bonds
48
Why does diamond have a higher melting point melting point?
Lots of energy is needed to break the strong covalent bonds so it has a higher melting point
49
Can diamond conduct electricity?
No - electrons are held in the shell and cannot move
50
What type of structure is graphite?
Giant covalent structure
51
How many covalent bonds does each carbon have in graphite?
3
52
Why does graphite’s carbon atoms only covalently bonded to 3 other carbon atoms?
There are no covalent bonds between the layers
53
How are the atoms arranged in graphite?
In hexagons that together form large flat sheets with are arranged on top of one another to form lots of layers
54
What is one single layer of graphite called?
Graphene
55
Why is graphite slippery?
The layers are held together by weak intermolecular forces and so they can slide over each other
56
Properties of graphite
Slippery
High melting point
Conducts electricity and heat
57
Does graphite have a low or high melting point?
High
58
Why does graphite have a higher melting point?
Individual layers are strongly held together by covalent bonds
59
Can graphite conduct electricity and heat?
Yes
60
Why can graphite conduct electricity and heat?
There are delocalised electrons between the layers which are free to move through the structure
61
Why is graphite useful in pencils?
The layers rub off onto the paper when they slide over each other
62
What is the chemical name for sand?
Silicone dioxide (silica)
63
How many of each atom is there is silicone dioxide (sand)?
1 silicone atom
2 oxygen atoms
64
Does sand have low or high melting point?
High
65
Why does sand have a higher melting point?
Giant covalent structure
66
Does sand conduct electricity?
No - no delocalised electrons
67
What is fullerenes?
Unusual covalent structures
68
What are fullerenes made of?
Carbon and form large molecules but they are not giant structures
69
What can graphene be used to make?
Sheets with pentagons or heptagons which make the sheets curve into a sphere
70
What are the uses of fullerenes?
Form them around other molecules like drugs to deliver them to certain areas in the body (carbon)
To make industrial catalysts (graphene, carbon)
Nanotubes used in nanotechnology and electronics (graphene, carbon)
Strengthen other materials (carbon)
Lubricants (graphene, carbon)
71
Why are nanotubes (tubes of graphene) used in nanotechnology and electronics?
They can conduct electricity
72
Why is carbon nanotubes used to strengthen other materials?
Tennis racket frames
Very high strength to weight ratio
—> can make them stronger without adding very much weight
73
What is an ion?
A charged particle
74
How is an ion formed?
When atoms gain or lose electrons to have a full outer shell so that they are more stable
—> requires energy
75
What does + mean?
Atom has lost an electron
76
What does - mean?
Atom has gained an electron
77
What is an ionic bond?
The electrostatic attraction between opposite charged ions
78
What does ionic bonding usually occur between?
Metals and non-metals
79
Are ionic bonds strong or weak?
Very strong
80
What are they then called when two atoms undergo ionic bonding?
Ionic compound
81
What does ionic bonding involve?
Metal atoms transferring their outer electron(s) to non-metal atoms
82
In ionic bonding the metal loses electron(s) and is therefore …?
Oxidised
83
In ionic bonding the non-metal atom gains electron(s) and is therefore ..?
Reduced
84
What type of atoms are ions?
Charged atoms
85
What does the atom become if it loses electron(s)?
A positive ion - because it has more protons than electrons
86
What does the atom become if it gains electron(s)?
A negative ion - because it has more electrons than protons
87
What do opposite charged ions do?
Attract and stick to each other
88
+ means the atom as been?
Oxidised
89
- means the atom has been?
Reduced
90
What happens when you put an ionic compound over a bunsen burner?
Nothing happens
91
What happens when you put an ionic compound in water?
It dissolves
92
What happens when you connect an ionic compound to a bulb?
Bulb doesn’t light
93
What happens when you connect an ionic compound (in water) to a bulb?
Bulb lights up
94
What happens when you put an ionic compound under a microscope?
Cube-shaped crystals are visible
95
Do ionic compounds have low or high melting and boiling points?
High
96
Why do ionic compounds have high melting points?
They have lots of really strong ionic bonds which require lots of energy to break them
97
Can ionic compounds conduct electricity as a solid?
No
98
Can ionic compounds conduct electricity when melted or dissolved in water?
Yes
99
Why can ionic compounds conduct electricity when melted or dissolved in water?
The ions are free to move around and the movement of the charged particles allows them to conduct electricity
100
Why can’t ionic compounds conduct electricity as solids?
The ions are in a fixed position and cannot move around
101
How are ions formed?
By gaining or losing electrons
102
Ions can be …?
Positively or negatively charged
