C3 - Structure and Bonding

Question 1

What happens in ionic bonding?

Answer 1

-transfer of e- from metal to non-metal atom in a reaction

-forms strong non-directional electrostatic force of attraction between the oppositely charged ions

Question 2

What is an ionic compound?

Answer 2

-giant lattice structure of oppositely charged ions
-held together by strong ionic bonds

the spec says you should be familiar with the structure displayed

Question 3

Give some properties of ionic compounds:

Answer 3

-hard and brittle
-high M/BP (strong bonds)
-conducts when molten/dissolved (ions can move)

They are hard/brittle because it is difficult to make one layer of ions shift relative to another layer, due to the ions being oppositely charged

Question 4

Why would a metal chloride usually be a solid at room temperature?

Answer 4

-metal chlorides are usually ionic
-they have strong electrostatic forces of attraction between their oppositely charged ions
-which require a lot of energy to overcome
-so they are solid at room temperature because of their high melting points

Don’t just say strong ionic bonds for these questions as it isn’t enough, they want you to explain why the melting point is high

Question 5

Define covalent bonding:

Answer 5

-shared electron(s) between 2 non-metal atoms

-forms a strong directional ES force of attraction between the shared electron(s) and the 2 nuclei

Question 6

What is a molecule?

Answer 6

a fixed number of atoms covalently bonded together with weak IM forces between molecules

Question 7

What is the bonding diagram for nitrogen gas?

Answer 7

triple covalent bond, and a pair on either side

Question 8

What is the bonding diagram for hydrogen chloride?

Answer 8

single covalent bond, with chlorine having the other 6 electrons paired on the opposite side

Question 9

What governs the bulk properties of a simple molecular substance?

Answer 9

the weak intermolecular forces between the individual molecules

Question 10

Give 2 properties of simple molecular substances:

Answer 10

-low M/BP due to weaker intermolecular forces
-not conductors (made of uncharged molecules)

Question 11

Give 2 properties of polymers:

Answer 11

-higher M/BP than simple molecules (larger molecules, ^IM forces)
-usually solid at room temp.

Question 12

Give 5 properties of giant covalent structures:

Answer 12

-high M/BP (need to break ALL strong cov. bonds)
-insoluble in water
-hard + brittle
-insulators

Graphite is a slight exception as it is soft (due to the layers) and a conductor

Question 13

Define metallic bonding:

Answer 13

-strong ES non-directional force of attraction
-between the metal ions and the delocalised electrons that are free to move about the lattice structure

metals which lose more outer electrons will have more delocalised electrons, and will form a stronger metallic bond

Question 14

Give 3 properties of pure metals:

Answer 14

-high M/BP (strong metallic bonds)
-soft (malleable and ductile)
-conductors of heat/electricity (due to delocalised electrons)

electrons can transfer both heat and electricity

Question 15

What are alloys, and how are they different from pure metals?

Answer 15

-a mixture that is harder than pure metals

-different sized atoms distorts regular layers in the pure metal
-can no longer slide over each other as easily

Question 16

Explain the difference between hardness and strength:

Answer 16

-hardness is the resistance to being scratched
-strength is the ability to withstand a force without becoming deformed

-if something is hard, it is brittle (has a low resistance to impact)

Question 17

What does particle theory describe?

Answer 17

the different states of matter, and their differences in density

Question 18

What are the limitations of particle theory?

Answer 18

it assumes all particles are solid, inelastic, homogenous spheres with no forces between them

homogenous spheres means particles that are all the same

Question 19

Give some limitations of using dot and cross diagrams to represent molecules:

Answer 19

-doesn’t show its shape
-only 2 dimensional

Question 20

What is an allotrope?

Answer 20

different forms of the same element in the same physical state

Question 21

Describe the structure of diamond:

Answer 21

each carbon atom forms 4 strong covalent bonds with other carbon atoms in a giant covalent structure (tetrahedral)

diamond is an allotrope of carbon

Question 22

Describe the structure of graphite:

Answer 22

-each carbon atom forms 3 strong covalent bonds with other carbon atoms forming a giant covalent structure
-makes layers of hexagonal rings (graphene) with weak IM forces between the layers
-1 electron from each carbon atom is delocalised, and exists between the graphene layers

graphite is an allotrope of carbon

Question 23

Describe the differences in properties between graphite and graphene:

Answer 23

(graphite)
-soft, malleable, good conductor

(graphene)
-very strong, good conductor

Question 24

Explain why graphite can conduct electricity:

Answer 24

-each carbon forms a strong covalent bonds to 3 other carbon atoms in a giant covalent structure
-one electron per carbon atom is delocalised
-they can carry a charge through the graphite

Don’t say that it can carry current/electricity, its too vague and isn’t accepted

Question 25

Where is graphene used?

Answer 25

-composite materials
-electronics
-lubricants

Question 26

What are fullerenes?

Answer 26

molecules of carbon atoms that are hollow spheres/tubes

eg C60, Buckminsterfullerene

Question 27

Why are fullerenes good for drug delivery around the body?

Answer 27

they are hollow so they can fit other drug molecules inside them

Question 28

What are nanotubes and their properties? How are they used in industry?

Answer 28

-cylindrical fullerenes (hollow tubes of carbon atoms)

-very high length : diameter ratio, and high tensile strength
-useful for nanotechnology, electronics, and materials

Question 29

What are nanoparticles, and how do they compare to other types of particles?

Answer 29

-particles of the size 1-100nm diameter

-smaller than PM2.5 (100-2500nm) and coarse particles (dust) that are PM10 (2500nm-10,000nm)

Question 30

What property of nanoparticles makes it more useful than any other material?

Answer 30

-high SA:V, so it is far more reactive
-need less than its bulk material to have the same desired effect, so it is more sustainable in industry (less material used)

Question 31

Give 5 uses of nanoparticles:

Answer 31

-catalysts
-lubricants
-electronics
-cosmetics (sun cream and deodorant)
-medicine (drug delivery, cancer treatment, antimicrobial wound dressings)

cancer treatments often use gold nanoparticles that are heated using a laser, which vibrate a lot and damage the proteins in the tumour

Question 32

What are 3 risks that should be considered when using nanoparticles?

Answer 32

-explosive/highly reactive (high SA:V)
-can cause lung damage if inhaled
-atmospheric pollution + damages aquatic life

Question 33

How can you tell if an equation is balanced?

Answer 33

-it has the same number of atoms on both sides
-of the SAME TYPE

this lost you a mark in some ppq’s

Question 34

If you are stuck on a physical properties question, what is a always a good backup property to add?

Answer 34

if it is usually a solid/liquid/gas at room temperature, as you can just add it onto the statement about its melting/boiling point

Question 35

Why can a solution of sodium chloride conduct electricity?

Answer 35

-there are charged sodium and chlorine ions in the water
-which can move and carry a charge

Question 36

Explain why chlorine is more reactive than iodine:

Answer 36

-chlorine’s outer electrons are closer to the nucleus
-its nucleus exerts a stronger ES force of attraction on its outer electrons
-it can gain an electron more easily to complete its outer shell

Question 37

Why is hydrogen chloride a gas at room temperature?

Answer 37

-hydrogen chloride is made of small molecules
-it has weak IM forces
-requires very little energy to overcome

Don’t mention breaking bonds, only overcoming the forces