Topic 2- Bonding

Question 1

what does the term delocalised electron mean?

Answer 1

a free electron

Question 2

what is an isotope?

Answer 2

Different forms of the same element that have the same number of protons but a different number of neutrons

Question 3

Why is something a gas at room temperature??

Answer 3

• Made up of small molecules
• Weak intermolecular force
• Don’t require much energy to separate them

Question 4

How to tell what has the lowest boiling point?

Answer 4

It has a smaller atom it has a lower boiling point

Question 5

Can a metal be a gas at room temperature?

Answer 5

No

Question 6

Why in group 7 is the reactivity the other way round?

Answer 6

It only need to gain one electron
Because the atom is so small the electrons are close to the nucleus as it has fewer shells so the intermolecular force is stronger so it is easier to attract 1 electron so little energy is needed.
the reaction is reactive as you go down the group there are more shells increasing the distance between the nucleus is greater which means electrons aren’t attracted

Question 7

Why is group 1 more reactive at the bottom

Answer 7

Because the distance is longer meaning the intermolecular force isn’t strong which means little energy is needed to loose the electron so the electron gets lost easily making it more reactive because as you go down the periodic table the number of shells increases decreasing the intermolecular force between the outer electron weak

Question 8

why is so and so a gas

Question 9

The structure and properties of diamond

Answer 9

structure:
•4 covalent bonds between carbon atoms
Properties:
•Hard - 4 strong covalent bonds hold atoms rigidly in place.
•Does not conduct electricity- no free(delocalised) electrons to carry a charge
•High melting point- strong covalent bonds between atoms that need a lot of energy to overcome

Question 10

what is the structure and properties of graphite

Answer 10

Structure:
•3 strong covalent bonds between carbon atoms
•Free(delocalised) electron
Made of layers that easily slide over each other
•The carbon atoms form layers of hexagonal rings
•There are no covalent bonds between the layers
Properties:
•Soft- formed from layers that easily slide over each other
•Conducts electricity- has a free(delocalised) electron to carry a charge

Question 11

what are the uses for Dimond?

Answer 11

•Cutting tools as it is hard because it has 4 strong covalent bonds between the carbon atoms
e.g. diamond tipped glass cutters and oil rig drills

Question 12

What are the uses for graphite?

Answer 12

electrodes in batteries and in for electrolysis as it can conduct electricity because it has a delocalised electron

Question 13

what are fullerenes?

Answer 13

• A form of carbon

* Molecules of carbon with hollow shapes. Their structures are based on hexagonal rings of carbon atoms.

Question 14

what is a nanotube?

Answer 14

Long cylindrical molecules made from carbon atoms joined together by covalent bonds.

Question 15

what is a buckyball?

Answer 15

Molecules comprising carbon atoms joined together to form spherical or nearly spherical hollow structures.

Question 16

nanotubes properties

Answer 16

• high tensile strength(can withstand a lot of tension)
• strong
• Conduct electricity- delocalised electron

Question 17

List buckyballs properties

Answer 17

• weak intermolecular force exist between individual buckyballs
• Low melting point-little energy is needed to overcome these forces
• slippery and weak

Question 18

how many carbon atoms does buckminsterfullerene have?

Answer 18

Buckminsterfullerene, C60, has sixty carbon atoms joined by covalent bonds

Question 19

when are covalent bonds formed?

Answer 19

when two non metal atoms share pairs of electrons

Question 20

Why are covalent bonds strong?

Answer 20

because the shared electrons are attracted to the nucleus of both atoms

Question 21

What are metallic bonds?

Answer 21

Metallic bonds are the electrostatic attractions between positive ions and negative delocalised electrons.

Question 22

What do we call the bonds that form when non-metal atoms share pairs of electrons?

Answer 22

covalent bonding

Question 23

List the properties of metallic bonds

Answer 23

• Good conductors-delocalised electrons to carry a charge
• Malleable- can be hammered into sheets
• Ductile- Can be drawn into rods and wires

Question 24

Why are metals ductile and malleable?

Answer 24

Because the ions easily move over each other.

Question 25

what is an ion?

Answer 25

Electrically charged particle, formed when an atom or molecule gains or loses electrons.

Question 26

how big is a nanoparticle?

Answer 26

Between 1-100nm

Question 27

Some properties of nanoparticulate materials are different from the properties of the same material in bulk, as powders, lumps or sheets. This difference in properties is the result of two things:

Answer 27

• the tiny size of nanoparticles compared to the same material in bulk
• the large surface area to volume ratios of nanoparticulate materials compared to the same material in bulk

Question 28

risks of nanoparticles

Answer 28

• Inhale pass into cells possibly catalysing reactions that are harmful
• Toxic substances could bind to them because of their large surface area to volume ratio, harming health if the nanoparticles do get into the body.
• Risk to health

Question 29

Advantages of nanoparticles

Answer 29

• Advances in disease treatments, such as cancer treatments

* Better imaging + diagnostic equipment

Question 30

Uses of nanoparticles

Answer 30

• medical treatment
• cosmetics, deodorants and sunscreens
• electronics
• catalysts