Bonding, Structure and Properties of Matter Flashcards
1
Q
Ion
A
Charged particle formed when an atom/molecule loses/gains electrons to get a full outer shell
2
Q
What happens when metals form ions
A
- lose electrons
- form positive ions
3
Q
What happens when non-metals form ions
A
- gain electrons
- form negative ions
4
Q
How is charge of an ion determined
A
number of an electrons lost
5
Q
Most likely groups to form ions
A
- group 1
- group 2
- group 6
- group 7
6
Q
Types of bonds
A
- ionic
- covalent
- metallic
7
Q
ionic bond
A
Strong attraction between oppositely charged ions by electrostatic forces, caused by metals and non-metals reacting together
8
Q
What happens in an ionic bond
A
- metal atom loses electrons
- electrons transferred to non-metal
9
Q
What diagram shows ionic bonds
A
Dot and cross
10
Q
Limitations of dot and cross diagram
A
Doesn’t show 3D dimensional nature of structure
11
Q
Limitations of ball and stick diagrams
A
Gives no info about forces of attraction or movement of electrons to form ions
12
Q
Structure of ionic compound
A
Giant ionic lattice
13
Q
Structure of giant ionic lattice
A
- ions form closely packed regular lattice arrangement
- strong electrostatic forces of attraction between oppositely charged particles in all directions in lattice
14
Q
Properties of ionic compounds
A
- high melting points
- high boiling points
15
Q
Why do ionic compounds have high melting/boiling points
A
There are strong electrostatic forces of attraction between ions that take a lot of energy to overcome
16
Q
When can ionic compounds conduct electricity
A
When molten or dissolved in water
17
Q
Molten
A
Metled
18
Q
Why can ionic compounds conduct electricity when molten
A
Ions are free to move and carry a charge
19
Q
When can’t ionic compounds conduct electricity
A
When solid
20
Q
Why can’t ionic compounds conduct electricity when solid
A
ions held in place so can’t carry a charge
21
Q
What happens to some ionic compounds in water
A
- they dissolve
- ions separate and are free to move in solution
- carry electric charge and conduct electricity
22
Q
What is sodium chloride in real life
A
Table salt
23
Q
Structure of sodium chloride
A
- giant ionic lattice structure
- positive Na+ ions and negative Cl- ions arranged in repeating alternating pattern
- held together by strong electrostatic forces of attraction
24
Q
Empirical formula
A
- what atoms are in an ionic compound
- includes number of each atom
25
How to work out empirical formula
- find out what ions are in compound from diagram
- work out charges of ion
- balance charges so overall charge is 0 - gives you number of atoms of each ion/element
26
Covalent bond
- bond between non-metals
- electrons shared to get full outer shells
- positive nuclei attracted to shared electrons through electrostatic forces
27
Diagram to show covalent bonds
Dot and cross
28
Simple molecular substances
Substances made up of molecules containing a few atoms joined together by covalent bonds
29
Properties of simple molecular substances
- atoms within molecules held together by very strong covalent bonds
- forces of attraction between molecules very weak
- low melting/boiling points
- usually gas/liquid at room temperature
- melting/boiling points increase as molecules get bigger
- don't conduct electricity
30
Why do simple molecular structures have low melting/boiling points
To melt/boil, only have to break weak intermolecular forces (easy to do) - don't have to break covalent bonds
31
Why do melting/boiling points of simple molecular substances increase as they get bigger
- strength of intermolecular forces increases
- more energy needed to break them
32
Why can't simple molecular structures conduct electricity
Not charged so there are no free electrons to carry a charge
33
How do intermolecular forces change with size of molecule
As molecule size increases, intermolecular forces get stronger
34
Polymers
Long chains of repeating small units, forming a long molecule that has repeating sections
35
Forces within polymers
- atoms in polymers held together by strong covalent bonds
- polymer molecules have strong intermolecular forces between them
36
How are polymers drawn
- repeating section in brackets
- 'n' outside brackets showing number of sections
37
State of polymers at room temperature
Solid
38
Why are polymers solid at room temperature
Stronger intermolecular forces, requiring more energy to break them
39
What type of molecule are giant covalent structures
Macromolecules
40
Properties of giant covalent structures
- all atoms bonded to each other by strong covalent bonds
- high melting/boiling points
- usually can't conduct electricity
41
Why do giant covalent structures have high melting/boiling points
Lots of energy needed to break covalent bonds between atoms
42
Why don't giant covalent structures usually conduct electricity
Don't contain charged particles
43
Examples of giant covalent structures
- diamond
- graphite
- silicon dioxide
44
Allotrope
Different structural forms of the same element in the same physical state
45
Allotropes of carbon
- diamond
- graphite
- fullerene
46
Properties of diamond
- very hard
- high melting point
- doesn't conduct electricity
47
Why is diamond very hard
Each carbon atom forms 4 covalent bonds
48
Why does diamond have a high melting point
Covalent bonds are strong and need a lot of energy to break
49
Why doesn't diamond conduct electricity
No free electrons/ions to carry a charge
50
Properties of graphite
- each carbon atom forms 3 covalent bonds, creating sheets of carbon atoms arranged in hexagons
- layers held together weakly (no covalent bonds) so it is soft and slippery - good lubrication
- high melting point
- conducts electricity + thermal energy
51
Why does graphite have a high melting point
Covalent bonds require much energy to break
52
Why does graphite conduct electricity and thermal energy
Only 3 of carbons electron used in bonds - 1 electron delocalised and free to move
53
Graphene
- 1 layer of graphite
- sheet of carbon atoms joined together in hexagons
- 1 atom thick
- contains delocalised electrons to conduct electricity
54
Fullerene
- molecules of carbon shaped liked closed tubes **or** hollow balls
- made up of carbon atoms arranged in hexagon sometimes containing pentagons (rings of 5 carbon atoms) or heptagons (rings of 7 carbon atoms)
- can form nanotubes
55
Uses of fullerene
- delivering a drug into body - fullerene structure forms around other atoms/molecules and ‘cages’ them
- industrial catalyst - large surface area, individual catalyst molecules could be attached to fullernes
- lubrication
56
First fullerene to be discovered
Buckminsterfullerene
57
Molecular formula of Buckminsterfullerene
C₆₀
58
What does Buckminsterfullerene form
Hollow sphere
59
Nanotubes
Tiny carbon cylinders
60
Properties of nanotubes
- high ratio between length and diameter
- conduct electricity + thermal energy
- high tensile strength so don't break when stretched
61
nanotechnology
Technology that uses very small particles like nanotubes
62
Uses of nanotubes
- strengthening materials without adding much weight
- used in electronics
63
What does metallic bonding occur in
Metallic elements and alloys
64
Metallic bonding
Strong electrostatic forces of attraction between positive metal ions and shared negative electrons, holding atoms together in a regular struture
65
Why do metals have high melting/boiling points
electrostatic forces between metal atoms and sea of delocalised electrons need lots of energy to be broken to melt/boil
66
Why are metals good conductors of electricity/heat
Delocalised electrons carry electrical charge + thermal energy through whole structure
67
Why are metals malleable
Layers of atoms can slide over each other
68
Why aren't metals always right for certain jobs
Often too soft when pure
69
How to deal with metals being too soft for certain jobs
Mix them with other metals to make them harder
70
Alloy
Mixture of 2 or more metals or a metal and another element
71
Why are alloys harder than pure metals
- different metals have different sized atoms
- when another element is mixed with a pure metal, new metal atoms will distort layers of metal atoms, making it more difficult fore layers to slide over each other
72
What determines what state something is a certain temperature
Strength of forces of attraction between particles of the material
73
What determines strength of forces of attraction between particles in a material
- material - structure of substance + types of bonds holding particles together
- temperature
- pressure
74
Criticisms of the particle theory model
- uses inelastic/spherical particles instead of atoms/ions/molecules
- doesn't show forces between particles so can't see how strong they are
75
Aqueous
dissolved in water
76
What happens when a solid is heated
- particles gain more energy and vibrate more, this weakens the forces holding the solid together
- at certain temperature (melting point), particles have enough energy to break free from their positions (melting) and turn into a liquid
77
What happens when a liquid is heated
- particles gain more energy and move faster
- bonds holding liquid together weaken and break
- at certain temperature (boiling point), particles have enough energy to break bonds (boiling) and turn into a gas
78
What happens when gases cool
- particles no longer have enough energy to overcome forces of attraction between them
- bonds form between particles
- as boiling point, so many bonds have formed between gas particles, it has condensed and become a liquid
79
What happens when liquids cool
- particles have less energy so move around less
- not enough energy to overcome forces of attraction between particles so bonds form between them
- at melting point, so many bonds have formed between particles, they're held in place
- liquid had frozen to become a solid
80
What determines amount of energy needed for a substance to change state
How strong forces between particles are
81
What kind of covalent bond does oxygen have
double bond ==
