C3 bonding

Question 1

how are covalent bonds formed

Answer 1

by atoms sharing electrons

Question 2

which type of atoms form covalent bonds between them

Answer 2

non-metals

Question 3

describe the structure and boding of a giant covalent substance

Answer 3

billions of atoms bonded together by strong covalent bonds

Question 4

describe the structure and bonding of small molecules

Answer 4

small numbers of atoms group together into molecules with strong covalent bonds between the atoms and weak inter molecular forces between the molecules

Question 5

describe the structure and boning of polymers

Answer 5

many identical molecules joined together by strong covalent bonds in a long chain, with weak intermoecular forces between the chains

Question 6

why do giant covalent substances have high melting points

Answer 6

it takes a lot of energy to break the strong covalent bonds between the atoms

Question 7

why do small molecules have low melting points

Answer 7

only a small amount of energy is needed to break the weak intermlecular forces

Question 8

why do large molecules have higher melting and boiling points than small molecules

Answer 8

the intermolecular forces are stronger in large molecules

Question 9

why do most covalent substances not conduct electricity

Answer 9

do not have delocalised electron or ions

Question 10

describe the structure an bonding of graphite

Answer 10

each carbon atom is bonded to three others in hexagonal rings arranged in layers- it has delocalised electrons and weak forces between the layers

Question 11

why can graphite conduct electricity

Answer 11

the delocalised electrons can move through the graphite

Question 12

explain why graphite is soft

Answer 12

layers are not bonded so can slide over each other

Question 13

what is graphene

Answer 13

one layer of graphite

Question 14

give two properties of graphene

Answer 14

strong, conducts electricity

Question 15

what is a fullerene

Answer 15

hollow cage of carbon atoms arranged as a sphere or a tube

Question 16

what is a nanotube

Answer 16

hollow cylinder of carbon atoms

Question 17

give two properties of nanotubes

Answer 17

high tensile strength, conduct electricity

Question 18

what is an ion

Answer 18

atom that has lost or gained electrons

Question 19

which kinds of elements form ionic bonds

Answer 19

a metal with a non-metal

Question 20

what charges do ions from group 1 and 2 form

Answer 20

group 1 forms 1+, group 2 forms 2+

Question 21

what charges do ions from group 6 and 7 form

Answer 21

group 6 forms 2-, group 7 forms 1-

Question 22

name the force that holds oppositely charges ions together

Answer 22

electrostatic force of attraction

Question 23

give three uses of fullerenes

Answer 23

lubricants, drug delivery (spheres), high-tech electronics

Question 24

describe the structure of giant ionic lattice

Answer 24

regular structure of alternating positive and negative ions, held together by the electrostatic force of attraction

Question 25

why don't ionic substances conduct electricity when solid

Answer 25

ions are fixed in position so cannot move, and there are no delocalised electrons

Question 26

why do ionic substance have higher melting points

Answer 26

electrostatic force between positive and negative ions is strong and requires lots of energy to break

Question 27

when can ionic substances conduct electricity

Answer 27

when melted or dissolved

Question 28

why do ionic substances conduct electricity when melted or dissolved

Answer 28

ions are free to move and carry charge

Question 29

describe the structure of a pure metal

Answer 29

layers of positive metal ions surrounded by delocalised electrons

Question 30

describe the bonding in a pure metal

Answer 30

strong electrostatic forces between metal ions and delocalised electrons

Question 31

what are four properties of pure metals

Answer 31

malleable, high melting/boiling points, good conductors of electricity, good conductor of thermal energy

Question 32

explain why pure metals are malleable

Answer 32

layers can slide over easily

Question 33

explain why metals have high melting and boiling points

Answer 33

electrostatic forces between positive metal ions and delocalised electrons is strong and requires a lot of energy to break

Question 34

why are metals good conductors of electricity and of thermal energy

Answer 34

delocalised electrons are free to move through the metal

Question 35

what is an alloy

Answer 35

mixture of a metal with atoms of another element

Question 36

explain why alloys are harder than pure metals

Answer 36

different sized atoms disturb the layers, preventing them from sliding over each other

Question 37

how big are nano particles

Answer 37

1-100 nm

Question 38

how are nanomaterials different from bulk materials

Answer 38

nanomaterials have a much higher surface area to volume ratio

Question 39

what is the relationship between side length and surface area to volume ratio

Answer 39

as side length decreases by a factor of ten, the surface area to volume ratio increases by a factor of ten

Question 40

what are nano particles used for

Answer 40

used in healthcare, electronics, cosmetics, and catalysts