4.2- Bonding, Structure and the different properties of matter Flashcards

Question

How do you draw ionic compounds?

Answer 1

Dot and cross diagram

Answer 2

In a giant ionic lattice. The giant refers to the millions of ions The ionic refers to the type of bonding Lattice refers to the fact that the ions are put together in a regular repeating arrangement.

Answer 3

In an ionic lattice, the attraction between positive and negative ions happens in all directions, therefore ionic bonding is multi-directional.

Answer 4

Limitations of the dot and cross diagrams: Are not to scale Do not show the electrons moving

Answer 5

1. High melting/boiling points 2. Dissolve in water 3. Can conduct electricity when in liquid or aqueous form- NOT SOLID

Answer 6

This is because the electrostatic attraction between the ions (the ionic bonds) are very strong, and it takes a lot of energy to break them.

Answer 7

This is because the water molecules are able to separate the positive and negative ions from each other and still hold them together

Answer 8

This is because when it is in solid form, the particles are fixed in place and cannot move around. However, when it is in liquid form or in a solution, although the particles are close together, they can move around, and can therefore carry a charge through the structure.

Answer 9

A covalent bond is the electrostatic attraction between a shared pair of electrons and the positively charged nuclei of the atoms in the bond.

Answer 10

Covalent bonding is directional, as it only exists between the atoms in the bond, it doesn’t bond elsewhere. The bonding is directly between the shared pair of electrons.

Answer 11

1. Ball and stick diagram 2. Dot and cross diagram

Answer 12

Demonstrates the 3D shape of the molecule The size of the atoms and the lengths of the bonds are not to scale, as they look much larger than they should be.

Answer 13

Hydrogen can only ever form 1 covalent bond Group 7 atoms- need one more electrons so they form 1 bond Group 6 atoms- need two more electrons so they form 2 bonds Group 5 atoms- need three more electrons so they form 3 bonds

Answer 14

A metallic bond is the electrostatic attraction between a lattice of positive metal ions and the sea of delocalised electrons. The lattice means that it is a regular repeating arrangement of layers of positive metal ions The sea of delocalised electrons are electrons that are scattered throughout the structure.

Answer 15

electrons that still come from the original atom, but have been lost from the outer shell of the metal. These are free to move around.

Answer 16

1. Conduct electricity 2. Conduct heat 3. High melting/boiling points 4. Malleable (shaped without breaking) 5. Ductile (shaped into wires)

Answer 17

The delocalised electrons carry electric current or thermal energy through the structure.

Answer 18

metallic bond is very strong and it takes a lot of energy to break the atoms apart.

Answer 19

This is because although the metallic bonds are strong, the layers of metal ions can slide past each other quite easily, as even if the ions shift, the delocalised electrons keep everything together.

Answer 20

Metal alloys are a mixture of a metal and one or more other substances (which can be metals or non-metals).

Answer 21

As pure metals are malleable and ductile, it often means that they are too soft for many uses. Alloys are generally harder and stronger than pure metals.

Answer 22

This is because an alloy is a mixture of substances, and they are in a random arrangement, with the atoms that are mixed in with the pure metal disrupting the regular layers of the metal. This makes it more difficult for the layers to slide past each other, making it harder for them to change shape or break the substance down.

Answer 23

(s)- solid (l)- liquid (g)- gas (aq)- aqueous/solution

Answer 24

1. Strong covalent bond 2. Weak intermolecular forces (between the molecules) 3. Low melting/boiling points 4. Cannot conduct electricity 5. Larger the molecule, stronger the intermolecular forces

Answer 25

This is because it is very easy to break the molecules apart from one another. When a simple covalent structure is melted, the weak forces of attraction between each molecule break, not the forces of attraction inside the molecule.

Answer 26

This is because all of the electrons are used up in the covalent bond, and there are no free electrons that can move around or carry a charge.

Answer 27

1. High melting/boiling points 2. Cannot conduct electricity

Answer 28

This is because it needs a lot of energy to overcome the strong attraction between the atoms in the covalent bonds.

Answer 29

This is because there are no free electrons to carry a charge

Answer 30

Allotropes are pure forms of the same element but with different structures

Answer 31

Each of the blue spheres represents a carbon atom- all of the atoms in diamond are carbon Each of the lines represents a strong covalent bond Each carbon atom in diamond has 4 covalent bonds

Answer 32

1. Hard 2. High melting point 3. Doesn't conduct electricity

Answer 33

This is because all of the carbon atoms are joined together by very strong covalent bonds

Answer 34

This is because all of the carbon atoms are joined together by very strong covalent bonds

Answer 35

This is because in diamond, all of the electrons are fixed and held tightly together within the covalent bonds. This means that they are not able to flow/move.

Answer 36

All of the blue atoms are carbon atoms- all of the atoms in graphite are carbon atoms. The thick black lines represent the strong covalent bonds The dashed lines represent the weak intermolecular forces between each layer of graphite Each carbon atom has 3 covalent bonds- leaving one delocalised electron that can move between the layers of graphite. Graphite is arranged in hexagonal layers- and each layer is separate.

Answer 37

1. Can conduct electricity 2. Has a high melting and boiling point 3. Quite soft

Answer 38

This is because of the delocalised electrons which can move between the layers and can carry a charge through the structure.

Answer 39

This is because the strong covalent bonds require a lot of energy to break

Answer 40

This is because there are weak intermolecular forces between the hexagonal layers, so they are able to slide past one another.

Answer 41

Fullerenes are another allotrope of carbon. They are hollow giant covalent structures.

Answer 42

They are made of hexagonal rings of carbon atoms covalently bonded (sometimes the rings contain 5 or 7 carbon atoms). They can also contain pentagons and heptagons as part of the structure.

Answer 43

The first fullerene discovered was Buckminsterfullerene (C60), so it is a structure containing 60 carbon atoms joined together. This is a simple covalent structure. It looked like a ball - earning the name ‘Bucky Ball’.

Answer 44

1. Low melting point 2. Doesn't conduct electricity

Answer 45

Weak intermolecular forces between molecules These require little energy to overcome- so buckminsterfullerene is slippery and has a low melting point.

Answer 46

Despite buckminsterfullerene having delocalised electrons, these electrons cannot move from one molecule to another, meaning that they cannot carry a charge.

Answer 47

Nanotubes- thin cylindrical layers of carbon atoms arranged similarly to graphene layers:

Answer 48

Length greater than diameter High tensile strength (resist being stretched and are therefore used to reinforce composite materials) High conductivity (delocalised electrons that can carry a charge through the structure.)

Answer 49

They have a high tensile strength- so they can be used to reinforce composite materials like sports equipment (eg. tennis rackets) Carbon is unreactive- allowing us to use them for drug delivery in the body Speed up chemical reactions (catalysts) High SA to V ratio- making them useful as catalysts and lubricants Hollow- can deliver drugs Can be used as lubricants (to reduce friction)

Answer 50

Graphene is a single layer of graphite that is one atom thick. It is 2-dimensional, rather than 3-dimensional

Answer 51

Very low density Strong for its mass High melting point/boiling point- as it is a giant covalent structure Flexible Electrical + thermal conductor (better than graphite)

Answer 52

Nanoscience studies structures that are between 1 nanometre (nm) and 100 nanometres (nm) in size. These structures are often only a few hundred atoms in size or smaller.

Answer 53

1 nanometre (nm) = 1 × 10⁻⁹ metres (m).

Answer 54

Because at the nanoscale, materials can behave very differently from their bulk form due to the high proportion of atoms at the surface, leading to unusual physical and chemical properties.

Answer 55

1 µm = 1 × 10⁻⁶ m, which is 1,000 nm.

Answer 56

PM10 stands for particulate matter with a diameter of 10 micrometres or less. These are referred to as coarse particles, often including dust and other pollutants.

Answer 57

These are fine particles with diameters between 0.1 µm (100 nm) and 2.5 µm (2500 nm). Nanoparticles are at least 100 times smaller than these.

Answer 58

Nanoparticles can be 100 times smaller than the finest dust particles — this is two orders of magnitude smaller, as 10² = 100.

Answer 59

As the side of a cube decreases by a factor of 10, its surface area to volume ratio increases by 10, making it much more reactive.

Answer 60

Because their high SA:V ratio makes them more reactive, so less material is needed to achieve the same effect — making processes more efficient and sustainable.

Answer 61

Their large surface area allows more reactant particles to interact, so reactions occur more quickly and efficiently. This is widely used in industrial chemistry.

Answer 62

Fullerene nanoparticles can deliver drugs directly to specific cells or tissues, such as targeting cancer cells, reducing side effects on healthy cells.

Answer 63

Carbon nanotubes have excellent electrical conductivity, making them ideal for miniaturised, high-speed computer chips and circuits.

Answer 64

Nanoparticles allow white substances like titanium dioxide to become transparent, as they are smaller than the wavelength of visible light, allowing light to pass through.

Answer 65

They can have antimicrobial properties, killing bacteria that cause bad smells, making the deodorant more effective.

Answer 66

Because nanoparticles are tiny enough to be inhaled, they may enter the lungs and bloodstream, with unpredictable effects on human cells and overall health.

Answer 67

Their high reactivity could cause explosions if a spark occurs near a large amount of nanoparticle catalyst, especially in poorly controlled environments.

Answer 68

It is limited. Because nanoparticles are relatively new, there’s still much to learn about their long-term effects on health and the environment, so regulation is cautious.

Answer 69

They allow for smaller quantities of materials to be used due to their efficiency, reducing waste and resource use, which supports greener industrial processes.

Answer 70

Potential future uses include nanowires (for flexible electronics), nanotube sensors (for chemical detection), and nanotech suits (for advanced materials and protection).