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GCSE Chemistry > Structure and Bonding > Flashcards

Structure and Bonding Flashcards

1
Q

Diagram for solid, liquid and gas.

A

Have you drawn arrows in liquid and gas?
What is the relationship between each particle, are they stuck tg or not?
Check

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2
Q

SOLIDS
- Compression ability
- Shape
- Can particles move?

A
  • Hard to compress because there are almost no spaces between particles
  • They have a fixed shape because particles are not free to move (can’t flow)
  • Particles can ONLY vibrate in a solid
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3
Q

LIQUIDS
- compression ability
- shape
- can particles move?

A
  • Hard to compress because almost no spaces between the particles
  • They don’t have a fixed shape and particles are free to move (can flow)
  • Liquids take the shape of their container
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4
Q

GASES
- compression ability
- shape
- can particles move?

A
  • Easily compressed because particles have a lot of spaces between them
  • They don’t have a fixed shape, gas particles are free to move - the move randomly and quickly
  • So they fill the shape of their container
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5
Q

How can the state of a substance be changed?

A

By putting in or taking out energy from the substance

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6
Q

Solid to liquid

A

= MELTING

  • Thermal energy is input into the solid substance and solid’s particles have more KE
  • Particles can vibrate and intermolecular forces of attraction are broken.
  • This occurs at the melting point.
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7
Q

Liquid to gas

A

BOILING

  • Thermal energy is input into the liquid substance so its particles have more KE
  • Particles vibrate and IMF are broken
  • This occurs at the boiling point
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8
Q

gas to liquid

A

= CONDENSATION

  • Thermal energy is removed from the gas so its particles have less KE
  • Particles move less and IMF are reformed
  • Condensation occurs at the same temperature as boiling of the liquid. (cool it down to its Bp temp)
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9
Q

liquid to solid

A

FREEZING

  • Thermal energy is taken out from liquid particles so they have less KE so less movement
  • IMF are reformed
  • Freezing takes place when we cool a liquid back down to its melting point temp
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10
Q

The stronger the IMF forces of attraction, the _____ energy needed to break the bonds, this means it has a higher what?

A

More energy
Higher melting point/boiling point

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11
Q

Limitations of the simple particle model of matter x2

A
  • Assumes that all particles are solid inelastic spheres, this isn’t true particles have lots of shapes and aren’t always solid
  • In SPM, assumes there are no IMF of attraction, not true, IMFOA are what keep particles tg in solid + liquid
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12
Q

Why do elements react?

A

Elements react so they achieve a full outer energy level to achieve the stable electronic structure of a noble gas (full outer shell)

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13
Q

When a metal and a non-metal react, what type of bonding takes place?

A

Ionic bonding

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14
Q

What happens during the ionic bonding between group 1 metals and group 7 non-metals?

A
  • Group 1 metal lose 1 electron and become a 1+ ion (1)
  • That electron is gained by the group 7 non-metal atom to become a 1- ion (1)
  • Both atoms now have a full outer shell (1)
  • This occurs during ionic bonding to form a metal halide compound(1)
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15
Q

How do we represent ionic bonding?

A

Dot and cross diagram, only showing outermost energy level.

  • OR energy level diagrams.
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16
Q

Describe what happens during ionic bonding between a group 2 and group 6 atoms

A
  • Group 2 metal lose 2 electrons and become a 2+ ion (1)
  • The 2 electrons are gained by the group 6 non-metal atom to become a 2- ion (1)
  • Both atoms now have a full outer shell (1)
  • This occurs during ionic bonding
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17
Q

Describe what happens during ionic bonding between a group 7 and group 2 atom

A
  • Group 2 metal lose 2 electrons and become a 2+ ion (1)
  • Those electrons are gained by 2 group 7 non-metal atoms (1 to each) to each become a 1- ion (1)
  • Both atoms now have a full outer shell (1)
  • This occurs during ionic bonding to form a metal halide compound(1)

*remember to always balance equations and write electronic structure in numbers in brackets + ALWAYS CHECK

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18
Q

True or false many ionic compounds are crystals?

A

True.

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19
Q

Ionic compounds are formed from what type of bonding?

A

Ionic bonding

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20
Q

Describe the structure of ionic compounds.

A
  • Form giant ionic lattices (giant ionic structures)
  • 3 dimensional
  • Every positive ion is surrounded be a negative ion and vice versa - so strong electrostatic forces of attraction.
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21
Q

What is a lattice?

A

The regular three-dimensional arrangement of ions in an ionic compound, held together by strong electrostatic forces of attraction.

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22
Q

What type of bonds hold ionic compounds together?

A

Strong electrostatic forces of attraction -> these act in all directions and hold the positive and negative ions in place.

so why do ionic compounds have high melting and boiling points?

  • They have strong electrostatic forces of attraction between ions.
  • Cannot conduct electricity because ions are locked in place by strong electrostatic forces of attraction, so are not free to move and carry electrical charge.
    ^^can only conduct electricity when molten or dissolved in water - as ions can now move and carry electrical charge.
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23
Q

Electrostatic forces of ATTRACTION is also known as?

A

Ionic bonds

(+ and -)

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24
Q

On spec, look at the diagrams that ionic bonds can be displayed.

A

Check, and draw

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25
Q

What is covalent bonding?

A

When a non-metal and non-metal bond tg. (2 non metals).

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26
Q

Example of covalent molecule

A

H2 (hydrogen)

^diatomic, only 1 electron on outermost shell of ONE hydrogen atoms, so covalently bonds w another and their outermost shell overlap to form covalent molecule H2 - both H atoms have are stable and achieve structure of noble gas.

Same thing occurs w group 7, overlap outermost energy level 2 get 1 extra electron in each.

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27
Q

True or false, covalent bonds are strong?

A

True

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28
Q

3 diagrams to represent bonding:

A
  • Stick diagram (eg F - F or C = C)
  • Dot and cross diagram
  • Energy level diagram (circles overlap)
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29
Q

True or false, only the outer energy levels are involved in chemical bonding?

A

True, that why we only draw them in bonding diagrams

Practice

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30
Q

Draw covalent bond for hydrogen and chlorine in stick diagram, dot-cross diagram and energy level diagram

A

check

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31
Q

Draw covalent bond for water and stick diagram, dot-cross diagram and energy level diagram

A

Water H2O , check diagrams

  • H has 1 electron on outermost shell and need to more to become stable
  • O has 6 electrons on outermost shell and need 2 more to become stable
  • So to H atoms bond w the O
  • So the 2 H atoms and O outermost shell overlap and covalently bond to for the covalent compound H2O
  • They are now stable and have achieved electronic structure of noble gas, full outermost energy shell

same principle for methane, CH4 and ammonia, NH3

32
Q

Number of pairs of electrons on intercept represents

A

each bond

33
Q

Draw stick, dot-cross and energy level diagrams for the following:

  • O2 oxygen
  • H2 hydrogen
  • N2 nitrogen
  • NH3 ammonia
  • CH4 methane
  • Cl2 chlorine
A

check

34
Q

N2 has how many bonds?

A

3

35
Q

O2 has how many bonds?

A

2

36
Q

True or false, covalent molecules are small?

A

True.

37
Q

Explain why covalent molecules have low melting and boiling points?

A
  • Strong covalent bonds between atoms in a molecule.
  • But weak IMF of attraction between molecules in a substance.
  • So not allow of energy is required to break them.
  • So low melting and boiling points.

^^This is why most small covalent molecules are gases at room temperature.

38
Q

True or false, as the size of the covalent molecule increases, the IMF of attraction between molecules increases?

A

True

39
Q

Explain why small covalent molecules don’t conduct electricity?

A

They have no overall electric charge.

  • So no free ion to carry electrical charge (no delocalised electron unlike ionic compounds).
40
Q

True or false, covalent molecules have an overall charge?

A

False

41
Q

Give 3 examples of giant covalent molecules:

A
  • Diamond
  • Silicon
  • Graphite
42
Q

Describe the state of covalent molecules at room temp:

A
  • Always solids at room temperature due to millions of strong covalent bonds which require a lot of energy to be broken and overcome.
  • This means they have a high melting and boiling point.
43
Q

What element is diamond made from?

A

Carbon.

44
Q

Information about diamond

A
  • Made from carbon molecule
  • Each carbon molecule forms 4 covalent bonds.
  • So very hard
  • Because made from many carbon molecules there are millions of strong covalent bonds, meaning that diamond has a high melting and boiling point because a lot of heat energy is required to break the bonds.
  • Cannot conduct electricity because there are no electrons that are free to move to carry electrical charge.
45
Q

What is silicon dioxide made from?

A

Silicon and Oxygen covalently bonded together.

46
Q

Information about silicon dioxide

A
  • Because it is a giant structure, there are many covalent bonds, this means that the MP and BP is high bc a lot of energy is required to break these covalent bonds.
  • Does not conduct electricity - no free/delocalised electrons.
47
Q

What is graphite made from?

A

Carbon.

48
Q

Information about graphite

A
  • Made from the element carbon
  • Each carbon atom forms three covalent bond, bc many carbon atoms means many covalent bonds = higher mp and bp bc lots of energy required to break bonds.
  • These covalent bonds make hexagonal rings which are arranged in layers with no covalent bonds between layers, these layers slide over each other making graphite soft and slippery bc layers can move.
  • Graphite conducts heat and electricity rlly well bc due to fact that carbon atoms only form 3 bonds, it means each carbon atom has a delocalised electron that is free to move.
  • This means the electron can move and carry electricity and heat.
49
Q

Draw and recognise diagram for graphite, diamond and silicon dioxide.

A

Check.

50
Q

Information on graphene

A

What is it made from? A single layer of graphite, so made from carbon atoms; 1 cm thick.

  • Good conductor of heat and electricity due to delocalised electrons (making it useful in electronics)
  • Strong - due to tightly packed hexagonal lattice structure of carbon atoms (making it useful for new materials)

USES
- Electronics
- Useful for new materials

51
Q

Information about fullerenes

A

What are they, molecules of carbon atoms that form hollow shapes, carbon atoms are covalently bonded to form hexagonal rings, but can have rings with 5 or 7 carbon atoms

52
Q

What was the first fullerene to be discovered, and how many C atoms does it have?

See image.

A

Buckminsterfullerene (C60), 60 carbon atoms.

It has a spherical shape.

53
Q

What can buckminsterfullerene be used for?

A
  • Lubricants (spherical hexagonal and hollow shape, stops moving parts from grinding together).
  • To deliver pharmaceuticals in the body
  • Catalysts
54
Q

Uses of buckminsterfullerene?

A
  • Lubricants, stopping grinding parts slide over each other.
  • Catalysts
  • Deliver pharmaceuticals in the body.
55
Q

Aside from buckminsterfullerene, give another example of a fullerene.

A

Carbon nanotube

56
Q

Information about carbon nanotubes:

A

Carbon nanotubes are cylindrical fullerenes with very high length to diameter ratios. Their properties make them useful for nanotechnology, electronics and materials.

  • Made from hexagonal rings of the element carbon to form a cylindrical shape.

PROPERTIES
- Have a very high length to diameter ratio.
- High tensile strength - so used to reinforce metals.
- Excellent conductors of electricity and heat due to delocalised electrons.
- Used to reinforce materials eg tennis rackets.

57
Q

Information about carbon nanotubes:

A

Carbon nanotubes are cylindrical fullerenes with very high length to diameter ratios. Their properties make them useful for nanotechnology, electronics and materials.

  • Made from hexagonal rings of the element carbon to form a cylindrical shape.

PROPERTIES
- Have a very high length to diameter ratio.
- High tensile strength.
- Excellent conductors of electricity and heat due to delocalised electrons
- Used to reinforce materials eg tennis rackets.

58
Q

Uses of carbon nanotubes:

A
  • nanotechnology
  • electronics
  • reinforcing materials

due to properties such as
- good conductor of heat and electricity
- high tensile strength

59
Q

What are polymers:

A
  • Polymers are made from monomers, the polymer takes the name, Poly(name of monomer), eg a polymer made from ethene will be called poly(ethene).
  • A monomer has a double C=C covalent bond, but when it reacts during polymerisation, this breaks, so polymers consist of SINGLE C-C covalent bond.
  • Because consists of covalent bond they are strong so useful for many materials eg textiles, food packaging.
  • Instead of writing polymers long hand way we can draw using repeating unit.
  • Repeating unit shows:

n meaning large number
single C-C covalent bond
two bonds on either side coming out of bracket to show it continues.

TRUE OR FALSE, polymers are solids at room temperature?

True, because of the strong intermolecular forces of attraction between each monomer, so a lot of energy is required to overcome these forces.

60
Q

What is meant by a polymer?

A

A large molecule consisting of group of monomers covalently bonded together.

61
Q

What is a monomer?

A

A small molecule that can join together with other monomers to form a larger molecule called a polymer through a process called polymerisation.

62
Q

Information about polymers and polymerisation:

A
  • Polymers are made from monomers, the polymer takes the name, Poly(name of monomer), eg a polymer made from ethene will be called poly(ethene).
  • A monomer has a double C=C covalent bond, but when it reacts during polymerisation, this breaks, so polymers consist of SINGLE C-C covalent bond.
  • Because consists of covalent bond they are strong so useful for many materials eg textiles, food packaging.
  • Instead of writing polymers long hand way we can draw using repeating unit.
  • Repeating unit shows:

n meaning large number
single C-C covalent bond
two bonds on either side coming out of bracket to show it continues.

TRUE OR FALSE, polymers are solids at room temperature?

True, because of the strong intermolecular forces of attraction between each monomer, so a lot of energy is required to overcome these forces.

63
Q

Describe the structure of metals?

A
  • Giant structure of atoms, arranged in regular layers.
64
Q

Information about metals and alloys.

A
  • Metals are a giant structure of atoms arranged in regular layers
  • Each atom in a metal has a delocalised electron on its outer energy level that is free to move and carry electrical charge and heat energy.
  • All these delocalised electrons form a sea of delocalised electrons (see image).
  • The sea of negative delocalised electrons are attracted to the positive charge of the metal ions (remember they are ions bc these delocalised electrons are lost and free to move)
  • This attraction is known as a strong electrostatic force of attraction and also known as metallic bond.
  • So in metals the metallic bonds are very strong making them solids at room temperature, bc they have a high melting and boiling point; (lots of energy required to overcome metallic bonds/esfa).

WHY CAN METALS BE BENT AND SHAPED?
- They are made from atoms arranged in regular layers, these layers can slide over each other,
- This means pure metals aren’t strong enough to make useful materials for things like jewellery, so we have alloyss

ALLOYS; a mixture of metals.
- The different size of the different atoms from the mixture of different metals distort the layers within the alloy, making it difficult for the atoms to slide over each other. This is why alloys are harder than pure metals.

65
Q

What is a millimetre in comparison to a meter?

A

1 x 10^-3 meters or 1/1000th of a meter.

1/1000 a millimeter = a micrometer

so a micro meter = 1 x 10^-6 meters

1/1000 micrometer = nano meter

a nano meter is 1 billionth of a meter

66
Q

What is meant by a nanoparticle?

A

A structure that is 1–100 nm in size, made up of a few hundred atoms.

They are smaller than fine particles but large than course particles.

67
Q

Fine particles:

A

AKA PM2.5 which have diameters between 100 and 2500 nm (1 x 10-7 m and 2.5 x 10-6 m)

68
Q

Coarse particles:

A

AKA PM10 have diameters between
1 x 10-5 m and 2.5 x 10-6 m.

Coarse particles are often referred to as dust.

69
Q

True or false, as the side of cube decreases by a factor of 10 the surface area to volume ratio increases by a factor of 10?

A

True

So nanoparticles may have properties different from those for the same materials in bulk eg catalysts because of their high surface area to volume ratio.

It may also mean that smaller quantities are needed to be effective than for materials with normal particle sizes.

70
Q

Give examples of uses of nano particles:

A
  • medicines
  • creams
  • deodorants
  • electronics
  • cosmetics
  • catalysts
71
Q

Risks of nanoparticles;

A

so small so can be absorbed by body into cells. We do not k the risk of this so this needs to continue to be studied carefully.

72
Q

Advantages and limitations of dot-cross diagrams

A

+ tell use which electron is coming from which atom

  • doesn’t show us the shape of the molecules involved
73
Q

Advantages and limitations of 2D stick diagrams

A
  • because covalent bonds are shown as a stick, we dont know where each electron comes from.
  • We aren’t shown any outer electrons which are not in bonds.
  • 2D -> not accurate info on the shape
74
Q

Advantages and limitations of 3D stick diagrams

A

+ show the shape
- we aren’t shown ideas of outer electrons that aren’t in bonds.
- shown as stick, so not shown which electron comes from which atom.

75
Q

Advantages and limitations of ball and stick diagrams.

A

+ Allow us to see the ions in 3D form
- Ions are widely spaced when in reality they are close tg
- Only show a PART of the giant crystal lattice - this gives a misleading depiction of its true size.

76
Q

Instead of ball and stick diagrams, we can used space filling diagrams, what are the advantages and limitations of these?

A

+ They allow us to see ions in 3D
+ Show ions closer tg, less misleading than ball and stick diagrams
- Only show a PART of the giant crystal lattice - this gives a misleading depiction of its true size.

GCSE Chemistry (9 decks)

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