Bonding

Question 1

what are some features of solids

Answer 1

1.particles in a solid are packed together in a regular pattern
2. solids have a fixed shape
in a solid, particles can vibrate but can’t move from place to place

Question 2

features of liquids?

Answer 2

they take the shape of their container and can move from place to place

Question 3

features of gases?

Answer 3

widely spaced
fill the space of their container

Question 4

what is the process
liquid to solid

Answer 4

freezing

Question 5

what is the process
solid to liquid

Answer 5

melting

Question 6

what is the process
gas to liquid

Answer 6

condensation

Question 7

why does NaCL have a high melting point

Answer 7

strong forces of attraction

Question 8

liquid to gas

Answer 8

boiling

Question 9

describe the limitations of the simple particle model of solid, liquids, and gases

Answer 9

1. assumes that all particles are solid spheres
2. assumed that there are no forces between the particles

Question 10

what is ionic bonding

Answer 10

when a metal and non metal react

Question 11

what type of structures do ionic compunds form

Answer 11

giant ionic lattice

Question 12

why do ionic compounds have high melting and boiling points

Answer 12

strong electrostatic atttraction between oppositely charged ions requires a lot of energy to overcome

Question 13

why can’t ionic compounds conduct electricity when they are solids

Answer 13

they have to be aqueous or molten, so ions are free to move to carrya charge and conduct electricity

Question 14

what is covalent bonding

Answer 14

when non metals bond together

Question 15

what is a covalent bond

Answer 15

when non metals share a pair of electrons

Question 16

what is a double covalent bond

Answer 16

when non metals share two pair s of electrons

Question 17

why do small covalent molecules have low melting and boiling points and why do they exist as gases at room temperature

Answer 17

.they have a strong covalent bond
. weak intermolecular forces, so doesn’t require a lot of energy to overcome

Question 18

what happens to the size of a covalent molecule as the intermolecular increases

Answer 18

size of the molecule increases

Question 19

what are the three giant covalent structures

Answer 19

diamond
graphite
sillicon dioxide

Question 20

describe some of the features of sillicon dioxide

Answer 20

1. sillicon and oxygen covalently bonded.
2. very high melting and boiling point due to the need to break numerous strong covalent bonds.
3. Always solids at room temperature.
4. Tetrahedral arrangement
5. semi conductor.

Question 21

describe some of the features of diamond

Answer 21

1. Each carbon atom forms covalent bonds with four other carbon atoms.
2. Carbon atoms have four electrons in their outer energy level.
3. Very high melting point and boiling point due to the energy required to break all covalent bonds.
4. doesn’t conduct electricty because there are no delocalised electrons.
5. Tetrahedral arrangement

Question 22

describe some features of graphite

Answer 22

1. Hexagonal sheets
2. weak intermolecular forces because they can slide over each other.
3. high melting point and boiling point
4. Good conductor of both electricity and heat
5. Each carbon atom is covalently bonded to three carbon atoms.
6. The hexagonal rings of carbon atoms are arranged into layers.
   There are no covalent bonds between the layers, which allows the layers to slide over each other. This makes graphite soft and slippery.

Question 23

why can graphite conduct electricity

Answer 23

It has delocalised electrons within the structure and it’s bonded to three carbon atoms leaving one electron free to move to carry an electrical charge and move freely throughout the structure

Question 24

why can’t diamond conduct electricity

Answer 24

. Each carbon atom is covalently bonded to four carbon atoms, this leaves no delocalised electrons that are free to move which are able to carry an electrical charge and move throughout the structure.

Question 25

what are the allotropes of carbon

Answer 25

graphite diamond fullerenes graphene

Question 26

describe some of the properties of graphene

Answer 26

1. Graphene is a single layer of graphite 2. good conductor of electricity 3. because it has delocalized electrons. These electrons can move through the graphene, carrying electrical charge. 4. high melting and boiling point due to a large number of strong covalent bonds. Breaking these bonds requires a great deal of energy.

Question 27

what are the uses of graphene

Answer 27

Useful in electronics due to its electrical conductivity. Useful for producing new materials due to its strength.

Question 28

give an example of a fullerene

Answer 28

buckminster fullerene

Question 29

how many carbon atoms does buckminster fullerene and how is it arranged

Answer 29

60 carbon atoms and the atoms are arranged in a hollow sphere.

Question 30

what is the use of buckminster fullerene

Answer 30

the space inisde buckminster fullerene is good for drug delivery into the body

Question 31

what are the uses of fullerenes

Answer 31

Drug Delivery Lubricants Catalysts

Question 32

what are some useful properties of nanoparticles

Answer 32

conduct electricity large surface area to volume ratio catalysts

Question 33

why are polymers solids at room temperature

Answer 33

strong intermolecular forces of attraction between molecules, breaking these forces require a lot of energy

Question 33

what are polymers ?

Answer 33

large molecules made from repeating monomers

Question 34

why do metals conduct electricity

Answer 34

the delocalised electrons move through the structure of positive metal ions in the metal structure and those electrons carry a charge

Question 35

describe a metallic bond

Answer 35

The strong electrostatic attraction between the sea of delocalized negative electrons and the positive metal ions.

Question 36

what are the properties of pure metals

Answer 36

high melting and boiling point malleable conductors of heat and electricity

Question 37

what is an alloy

Answer 37

mixture of two or more metals

Question 38

why are alloys harder than pure metals

Answer 38

. Different atoms or elements have different sized atoms. So when another metal is mixed with a pure metal , the new element/ atoms will distort the layers of metal atoms making it more difficult for them to slide over each other.

Question 39

what is the size of a nanometer

Answer 39

10^-9 of a metre.

Question 40

what is the size of nanoparticles

Answer 40

1 nm to 100nm

Question 41

what is the size of fine particles

Answer 41

100 nm to 2500 nm

Question 42

what is the size of coarse particles

Answer 42

2500 nm and upwards

Question 43

why is it that nano particles having large surface area to volume ratio is an advantage

Answer 43

we need less materials when using nano particles. a small amount of nanoparticles does the same job as bulk materials

Question 44

what are the uses of nano science

Answer 44

. Medicines Sun creams Cosmetics Deodorants Electronics Catalysts

Question 45

what is an advantage of Dot and Cross Diagram

Answer 45

Clearly shows the origin of electrons in a molecule, distinguishing electrons from different atoms through the use of dots and crosses.

Question 46

what is a limitation of a Dot and cross diagram

Answer 46

Fails to represent the actual shape of the molecule.

Question 47

what is the limitation of a 2D stick diagrams

Answer 47

: 1. Does not indicate which electron in a covalent bond originates from which atom. 2. Provides no information on outer electrons that are not involved in covalent bonds. 3. Inaccurate representation of the molecule's shape.

Question 48

what is one limitation of a 3D dot and cross diagrams

Answer 48

Illustrates the shape of the molecule.