2.1 - Bonding, structure and properties

Question 1

How do you find out the group number and period number of an element from its electronic structure?

Answer 1

Group number = number of electrons in the outer shell
Period number = number of shells

Question 2

What is an isotope?

Answer 2

An element that has the same number of protons but different number of neutrons

Question 3

What does ionic bonding occur between?

Answer 3

Metals and non-metals

Question 4

What is the attraction between ionic compounds? And what is it?

Answer 4

Electro static attraction.
Attraction between opposite charges/ions

Question 5

What are the properties of a giant ionic lattice?

Answer 5

-high melting point b/c strong electro static forces between ions need lots of energy to break
-soluble b/c ionic lattice disociates in water
-electrical conductivity (only when molten or dissolved) b/c ions are free to move about

Question 6

What does covalent bonding happen between? Are ions formed?

Answer 6

non-metals only
no ions formed

Question 7

What are the common molecules that contain double bonds?

Answer 7

Oxygen (O2), Carbon Dioxide (CO2), Carbon Sulphide

Question 8

What is the difference between intermolecular bonds and intramolecular bonds?

Answer 8

Intermolecular bonds are between molecules and are weak
Intramolecular bonds are within molecules and are strong

Question 9

What are the physical properties of simple covalent compounds?

Answer 9

-low melting/boiling point b/c intermolecular bonds and so don’t need lots of energy to break.
-don’t conduct electricity as no free electrons to move and carry charge

Question 10

What are two examples of Giant Covalent structures?

Answer 10

Diamonds and Graphite

Question 11

What are the properties of a Diamond?

Answer 11

1. Hard b/c strong covalent bonds
2. high melting point b/c strong covalent bonds
3. no free electrons to conduct electricity

Question 12

How many intramolecular bonds do each carbon atoms form?

Answer 12

4 strong intramolecular covalent bonds

Question 13

What are the uses of a Diamond?

Answer 13

drill bits because they have a high melting point

Question 14

What are the properties of Graphite?

Answer 14

1. Soft/slippery b/c weak intermolecular forces between layers
   2.high melting points b/c lots of strong covalent bonds
   3.conducts electricity b/c delocalised electrons

Question 15

How many intramolecular bonds does each carbon atom have?

Answer 15

3 strong intramolecular covalent bonds
The fourth electron is found delocalised between the layers

Question 16

Carbon can also form fullerenes. What is an example of a fullerene?

Answer 16

Buckminster fullerenes (buckyballs)

Question 17

What are the uses of bucky balls?

Answer 17

Drug delivery, lubricants, as catalysts and in nanotubes

Question 18

What are carbon nanotubes?

Answer 18

A type of fullerene

Question 19

What are the properties of nanotubes?

Answer 19

• among the stiffest and strongest fibres
• very strong b/c covalently bonded and free electrons give a high electrical conductivity

Question 20

What is graphene?

Answer 20

is similar to just one layer of the graphite molecule

Question 21

What are the properties of graphene?

Answer 21

• thinnest material known to man
• lightest material known to man
• strongest material known to man
• best conductor of electricity

Question 22

How is metallic bonding held together?

Answer 22

held together by electrostatic forces between delocalised electrons

Question 23

What are the properties of metallic bonding and why?

Answer 23

• high melting/ boiling points as strong electrostatic forces of attraction between positive metal ions and delocalised electrons
• conducts electricty as delocalised electrons free to move
• malleable as has regular structure and deloclised electrons which makes it easier for metal ions to slide over each other
• high density as closely packed structure

Question 24

What is the scale in a nanostructure?

Answer 24

1-100nm or 1x10 -9

Question 25

Silver is a nanomaterial. What does it do?

Answer 25

It kills bacteria (doctors use wound dressings containing silver to treat ext infections)

Question 26

Titanium dioxide is a nanomaterial. What does it do?

Answer 26

It absorbs and reflects harmful UV rays from the sun

Question 27

Butyl rubber is a nanomaterial. What does it do?

Answer 27

It slows down the escape of air so balls don't lose air quickly

Question 28

Zinc oxide is a nanomaterial. What does it do?

Answer 28

It absorbs and reflects harmful UV rays from the sun

Question 29

What is the definition of a smart material?

Answer 29

Smart materials have properties that change reversibly with a change in their environment.

Question 30

State the properties of thermochromatic pigments and their uses.

Answer 30

They change colour with changing temperature. Mugs that change colour

Question 31

State the properties of photochromatic pigments and their uses.

Answer 31

They change colour with changing light intensity Holiday T-shirt designs

Question 32

State the properties of hydrogels and their uses.

Answer 32

They absorb/expel water and shrink/swell due to changes in pH or temp Baby nappies

Question 33

State the properties of shape memory alloys and their uses.

Answer 33

Metals which regain their original shape when heated Kettle springs

Question 34

State the properties of shape memory polymers and their uses.

Answer 34

Plastics which regain their original shape when heated Gum shields