bonding, structure and properties of matter 2

Question 1

what are ions

Answer 1

are charged particles trying to lose or gain electrons to achieve a full outer shell

Question 2

what happens when metals form ions

Answer 2

they lose electrons to from positive ions

Question 3

what happens when non metals form ions

Answer 3

they gain electrons to from negative ions

Question 4

how many electrons do group two lose ( ions )

Answer 4

2 electrons

Question 5

how many electrons do group one lose ( ions )

Answer 5

1 electron

Question 6

how many electrons do group 6 gain ( ions )

Answer 6

2 electrons

Question 7

how many electrons do group 7 gain ( ions )

Answer 7

1 electron

Question 8

what is ionic bonding

Answer 8

when a metal and non metal react together the metal atom loses electrons to form a positively charged ion and the non metal gains these electrons to form a negatively charged ion. the oppositely charged ions are strongly attracted to one an another by electrostatic forces

Question 9

properties of an ionic compound

Answer 9

1) high melting and boiling point due to many strong bonds
2) when solid the ions are held in place so they don’t conduct electricity
3) when the ionic compound melts the ions are free to move and can conduct electricity
4) when compound dissolves in water the ions separate and are free to move in the solution

Question 10

what is covalent bonding

Answer 10

when non metal atoms bond together they share pairs of electrons to make covalent bonds.
the positively charged nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic forces, making covalent bonds very strong.

Question 11

properties of covalent bonding

Answer 11

1) very strong covalent bonds, by contrast the forces between these molecules are weak
2) only need to break inter molecule forces so the melting and boiling point is low
3) as they get bigger the intermolecule forces increases so more energy is needed increasing the melting and boiling point

Question 12

what is metallic bonding

Answer 12

electrons in the outer shell of the metal atoms are delocalised. There are strong forces of electrostatic attraction between the positive metal ions and the shared negative electrons
metallic bonding is very strong

Question 13

why are metals solid at room temp

Answer 13

electrostatic forces between the metal atoms and the delocalised sea of electrons are very strong so need lots of energy to be broken
This means that most compounds with metallic bonds have very high meting and boiling points.

Question 14

what makes metals good conductors of electricity and heat

Answer 14

delocalised electrons carry electrical current and thermal energy through the whole structure

Question 15

Why are metals malleable

Answer 15

atoms can slide over each other making malleable

Question 16

what is wrong with pure metals and what is done to improve it

Answer 16

they are soft so need to be mixed with other metals so they are harder

Question 17

Why are alloys strong

Answer 17

different sized atoms so will distort the layers of metal atoms making it difficult for them to slide over each over

Question 18

what is the diameter of a coarse particle

Answer 18

2500 nm and 10000 nm

Question 19

what is the diameter of a fine particle

Answer 19

100 nm and 2500 nm

Question 20

what is the diameter of a nano particle

Answer 20

1 nm and 100 nm

Question 21

surface area to volume ratio =

Answer 21

surface area / volume

Question 22

What happens as particles decrease in size

Answer 22

surface area increases in relation to volume

Question 23

uses of nano particles

Answer 23

1) used for catalysts because of there surface to volume ratio
2) tiny particles are absorbed more easily so are good for delivering drugs
3) they conduct electricity
4) silver nano particles have antibacterial properties making them good for medical equipment
5) used in cosmetics

Question 24

effects of nano particles on health

Answer 24

important that they are tested
some people worrie that the products have not been tested
people wont them to be labelled clearly
they can get in your body and effect the environment when washed off

Question 25

how are atoms joined in a polymer

Answer 25

strong covalent bonds

Question 26

why are most polymers solid at room temp

Answer 26

inter molecular forces between polymer molecules are larger than between simple covalent molecules so more energy is needed to break them

Question 27

properties of giant covalent structures

Answer 27

very high melting and boiling points as lots of energy is needed to break the covalent bonds
don’t conduct electricity because they don’t have charged particles.

Question 28

what are allotropes

Answer 28

different structural forms of the same element in the same physical state

Question 29

why is diamond hard

Answer 29

giant covalent structure made up of carbon atoms that each contain four covalent bonds

Question 30

other properties of diamond

Answer 30

take a lot of energy to break bonds so has a high melting and boiling point
dont conduct electricity because it has no free electrons

Question 31

what is the structure of Graphite

Answer 31

each carbon atom only forms three covalent bonds creating sheets of carbon atoms arranged in hexagons

Question 32

what makes graphite so soft and slippery

Answer 32

aren’t any covalent bonds between the layers, so are free to move over each over.

Question 33

Other properties of graphite

Answer 33

high boiling point because of covalent bonds

conducts electricity and thermal energy because there are delocalised electrons

Question 34

what is the structure of graphene

Answer 34

a sheet of carbon atoms joined together in hexagons

the sheet is one atom thick

Question 35

properties of graphene

Answer 35

light so can be added to composite materials to improve there strength without adding weight
conduct electricity because of its delocalised electron

Question 36

structure of fullerenes

Answer 36

are molecules of carbon shaped like closed tubes or hollow balls
mainly made up of carbon atoms arranged in hexagons, but can also contain pentagons

Question 37

why are fullerenes good catalysts

Answer 37

huge surface area

Question 38

how are fullerenes used to deliver drugs

Answer 38

used to cage other molecules by trapping them inside

Question 39

what are nano tubes

Answer 39

tiny carbon cylinders

Question 40

properties of nano tubes

Answer 40

conduct electricity
high tensile strength (don’t break when they are stretched)
ratio between length and diameter of nano tubes is high

Question 41

what can form nano tubes

Answer 41

fullerenes