C3 Structure and bonding Flashcards

1
Q

The ionic bonds between the charged particles result in an arrangement of ions called what?

A

a giant structure or giant lattice

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2
Q

What is between the oppositely charged ions in giant structures of ions arranged in a lattice?

A

attractive electrostatic forces that act in ALL directions and are very strong

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3
Q

What does the attractive electrostatic forces do?

A

holds the ions in the lattice together very tightly

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4
Q

It takes a lot of what to break up a giant ionic lattice and why?

A

Energy- lots of strong ionic bonds to break

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5
Q

How do we separate ions?

A

have to overcome all those electrostatic forces of attraction acting in all directions

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6
Q

Hard to separate means ionic compounds have..

A

high boiling+melting points

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7
Q

What happens to the ions once enough energy is supplied to separate the ions from the lattice

A

They become mobile and start to move around (solid to liquid)

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8
Q

Ions are ___ to ___ anywhere in the liquid

A

free

move

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9
Q

Why can’t a solid ionic compound conduct electricity?

A

ions are held in fixed positions in the lattice; ions cannot move around
They vibrate on the spot

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10
Q

Many but not all ionic compounds will dissolve in water. When an ionic compound is dissolved in water, what happens?

A

lattice is split up by the water molecules. -> ions free to move around within the solution formed

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11
Q

What is molten?

A

liquefied by heat.

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12
Q

What is covalent bonding

A

When non-metals react together, their atoms share pairs of electrons to form molecules

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13
Q

The atoms of non-metals generally tend to gain what?

A

gain electrons to achieve stable electron structures

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14
Q

When non-metals react together, neither atom can give away electrons. So where do they get their electronic structure?

A

They get their electronic structure of a noble gas by sharing electrons

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15
Q

In covalent bonding, the atoms in the molecules are then helped by what?

A

Shared pairs of electrons

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16
Q

The strong bond between the shared pairs of electrons are called?

A

covalent bonds

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17
Q

Many substances containing covalent bonds consist of what?

A

small molecules e.g. h20

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18
Q

Some covalently bonded substances are very different to those small molecules. What do they have?

A

giant structures - where huge numbers of atoms are held together by a network of covalent bonds

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19
Q

what are these covalent bonds in giant structures sometimes referred as?

A

macromolecules

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20
Q

Diamond has what sort of structure?

A

giant covalent structure

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21
Q

In diamond. how many covalent bonds does the carbon atom form?

A

4 covalent bonds w its neighbours

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22
Q

Since the carbon has 4 covalent bonds, what does this result in?

A

a rigid giant covalent lattice

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23
Q

What are dot and cross diagrams for?

A

to show bonding in covalent compounds

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24
Q

Electrons drawn in the ____ between the outer orbitals of two atoms are ____ between atoms in covalent bonding

A

overlap

shared

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25
Q

What are dot and cross diagrams useful for?

A

showing which atoms the electrons in a covalent bond come from

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26
Q

What is a drawback of dot and cross diagrams

A

Doesn’t show relative SIZES of the atoms

or how the atoms are arranged in space

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27
Q

Displayed formula is useful for?

A

shows how atoms are connected in LARGE molecules

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28
Q

drawback of displayed formula?

A

does not show 3d structure of the molecule

or which atoms the electrons in the covalent bond have come from

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29
Q

What does the 3D models show?

A

the atoms, the covalent bonds and their ARRANGEMENT in space

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30
Q

drwback for 3d models?

A

confusing for large molecules where there are lots of atoms to include
does not show where the electrons in the bonds have come from either

31
Q

The atoms within the molecules are held together by very ___ ______ bonds but the forces of _____ between these molecules are very ____

A

strong covalent
attraction
weak

32
Q

To melt or boil a simple molecular compound, do you need high or low boiling/melting point?

A

low- feeble intermolecular forces and not the covalent bonds, molecules are easily parted

33
Q

As molecules get bigger..

A

intermolecular forces increases - more energy needed

34
Q

Molecular compounds don’t of what and why?

A

conduct electricity- AREN’T CHARGED- no free electrons

35
Q

What are some properties of a giant covalent structure that gives substances?

A

high mp and bp
insoluble in water
Apart from graphite, hard and does not conduct electricity

36
Q

In graphite, carbon are only bonded to what?

A

three other carbon atoms

37
Q

What does the carbons form in graphite

A

hexagons, arranged in giant layers

38
Q

In graphite, there are no _____ bonds between the layers only weak ______ forces, so the layers can _____ over each other quite easily

A

covalent
intermolecular
slide

39
Q

Graphite is a ___ material that feels ______ to the touch

A

soft

slippery

40
Q

As the carbon atoms in graphite’s layers are arranged in hexagons, each carbon forms what?

A

three strong covalent bonds

41
Q

Carbon atoms have ___ electrons in their outer shell available for _____. This leaves one space outer ______ on each carbon in graphite

A

four
bonding
one
electron

42
Q

These mobile electrons can ____ freely along the ____ of carbon atoms. The mobile electrons found in graphite are called?

A

freely
layers
delocalised electrons

43
Q

Mobile electrons between the layers of graphite no longer what?

A

belong to any one particular carbon atom. They behave rather like the electrons in a metallic structure

44
Q

What do these delocalised electrons allow graphite to do?

A

conduct electricity- electrons will drift away from the negative terminal of a battery and towards its positive terminal when put into an electrical circuit

45
Q

Graphite is also an excellent conductor of what and why?

A

Thermal conductor

Energy is transferred to the delocalised electrons, rapidly transfer the energy along the LAYERS in the graphite

46
Q

Why can’t diamond conduct electricity?

A

their atoms have no free electrons, as all their outer shell electrons are involved in a covalent bonding

47
Q

What are fullerenes

A

structures where carbon atoms join together to make hollow cages

48
Q

Cyndrical fullerenes called carbon nanotubes can also be produced, they form what?

A

incredibly thin cylinders, whose length is much greater than their diameter

49
Q

What useful properties do incredibly thin cylinders have?

A

high tensile strength

high electrical conductivity and high thermal conductivity

50
Q

The atoms in metals are built up as?

A

layer upon layer in a regular pattern

51
Q

Regular pattern in atoms of metals mean?

A

that metals form crystals

52
Q

What is metal another example of?

A

giant structures

53
Q

A metal has a lattice of…

A

positively charged ions

54
Q

How are the metal ions arranged?

A

regular layers, on top of another

55
Q

What can the outer electrons from each metal atom do?

A

easily move throughout the giant strucutre

56
Q

In metallic structures, the outer electrons form what?

A

a ‘sea’ of free-moving electrons surrounding the positively charged metal ions

57
Q

What bonds the metal ions to each other?

A

Strong electrostatic attraction between the negatively charged electrons and the positively charged ions

58
Q

The sea of delocalised electrons are no longer ____ with any particular ____ __ in the giant metallic structure

A

linked

metal ion

59
Q

What is an alloy

A

a mixture of two or more elements

60
Q

Describe why metals can be bent, shaped and pulled out into wires when forces are applied?

A

layer of atoms (positively charged ions) slide over each other easily

61
Q

What word can be used to describe a material that can be hammered into shape and drawn out into wire?

A

malleable

ductile

62
Q

Using knowledge of metal structures explain why alloying a metal can make the metal harder?

A

differently sized atoms inserted
regular arrangement of metal atoms (positively charged ions) disrupted
more difficult for laters to move

63
Q

Explain why metals are good conductors of thermal energy and electricity?

A

sea of delocalised electrons drifting through metal’s giant structure.

mobile delocalised electrons gain energy when heated

64
Q

Explain why aluminium has a higher melting point than sodium

A

each aluminium donates 3 electrons into ‘sea’ of mobile delocalised electrons. Forming Al 3+ ions
Comparted to one electron in lattice of Na+ ions
Electrostatic forces of attraction in metallic bonding stronger in aluminium because of a higher charge + more electrons involved in metallic bonding

65
Q

What is meant by nanoscience?

A

study of particles between 1 and 100 nm in size

66
Q

explain why the properties of nanoparticles of a material may differ from the properties of a bulk material

A

normal materials: most atoms, molecules or ions exist within body of material- not exposed at surface of material
nanoparticles: proportion of particles at surface is massively increased for same mass of material so properties different

67
Q

Why might nanoparticles be different from those for the same materials in bulk

A

have a high surface area to volume ratio, with a high percentage of their atoms exposed in their surface

68
Q

Nanoparticles may result in smaller quantities of materials such as ____, needed for what?

A

catalysts

industrial uses

69
Q

Give two uses of silver nanoparticles

A
  • antibactericide in fridges
  • sprays in operating theatres,
  • wound dressings
  • on clothes
70
Q

Give an adv of using nanoparticles as catalyst

A

large surface area to volume ratio

71
Q

Why are some people concerned about the use of nanoparticles as catalysts?

A

EXPLOSIONS caused by sparks

HEALTH PROBLEMS if breathed in if nanoparticles escape into air / environment

72
Q

Explain two uses of nanoparticles in cosmetic products for the skin

A

Sun-screens- block UV light

face-cream: deliver active ingredients deeper beneath surface of skin

73
Q

How can nanoparticles possibly help to fight cancers

A

delivers drugs to the tumour and is then absorbed, then absorbs energy from lasers to damage tumour by affecting its proteins