4.1 - covalent bonding

Question 1

what is the formula for nitrate

Answer 1

NO₃ -1

Question 2

what is the formula for hydroxide

Answer 2

OH -1

Question 3

what is the formula for sulphate

Answer 3

SO₄ -2

Question 4

what is the formula for carbonate

Answer 4

CO₃ -2

Question 5

what is the formula for ammonium

Answer 5

NH₄ +1

Question 6

what is the formula for ammonia

Answer 6

NH₃

Question 7

what types of elements form ionic bonds

Answer 7

metals and non-metals

Question 8

where is the start of the staircase that splits the metals and the non-metals

Answer 8

in between aluminium (Al) and boron (B)

Question 9

what is meant by the term ionic bonding?

Answer 9

the strong electrostatic attraction between the positive and negative ions

Question 10

what type of structure do ionic compounds form?

Answer 10

giant ionic lattice

Question 11

give one property of an ionic compound and explain it

Answer 11

high melting point -
- giant ionic lattice
- strong electrostatic attraction between positive and negative ions
- therefore require immense energy to overcome

Question 12

what is a covalent bond?

Answer 12

the strong electrostatic attraction between pairs of shared electrons and positive NUCLEI

Question 13

what types of elements form covalent bonds?

Answer 13

non-metals

Question 14

what does - mean in H - Cl

Answer 14

1 pair of shared electrons therefore single (1) covalent bond

Question 15

what does = mean in O = O

Answer 15

2 pairs of shared electrons therefore double (2) covalent bonds

Question 16

what is the only thing we need to know about silicon dioxide

Answer 16

it is giant covalent

Question 17

what does graphite, coal and diamond have in common in terms of elements

Answer 17

all made from pure carbon

Question 18

explain why giant covalent substances have a high melting point

Answer 18

many strong covalent bonds therefore requires energy to break (only time you can break bonds)

Question 19

explain the conductivity of graphite

Answer 19

CONDUCTIVE:
- delocalised electrons are free to move
-each carbon is bonded to 3 others (therefore there are delocalised electrons which are free to move)

Question 20

explain the conductivity of diamond

Answer 20

NOT CONDUCTIVE:
- no delocalised electrons and no ions

Question 21

is graphite hard or soft and explain why

Answer 21

SOFT:
- layers can slide over each other

Question 22

is diamond hard or soft and explain why?

Answer 22

HARD:
- each carbon is bonded to 4 others (therefore very hard)

Question 23

what is a use for diamond?

Answer 23

drill bits

(if don’t remember say cutting glass)

Question 24

what is a use for graphite?

Answer 24

solid lubricant

Question 25

what structure does metallic bonding create?

Answer 25

giant metallic lattice

Question 26

what structure does ionic bonding create?

Answer 26

giant ionic lattice

Question 27

what structures do covalent bonding create?

Answer 27

giant covalent substances simple molecular substances

Question 28

explain the melting point of simple molecular substances

Answer 28

- low melting point - weak intermolecular forces require little energy to overcome

Question 29

explain the relationship between relative molecular mass and boiling point

Answer 29

- as relative molecular mass increases, boiling point increases - because the intermolecular forces are getting stronger - therefore require more energy to overcome

Question 30

what is an example of a simple molecular substance

Answer 30

C60 fullerene

Question 31

the boiling point of C60 fullerene is 600°C - this is low, but is higher than other simple covalent molecules. Explain why C60 fullerene has a boiling point of 600°C

Answer 31

- it has more atoms therefore has a higher molecular mass - therefore stronger intermolecular forces - therefore, higher boiling point/melting point

Question 32

what is a use of C60 fullerene

Answer 32

drug delivery (hollow)

Question 33

graphite is naturally occurring form of carbon explain why graphite is soft and conducts electricity refer to structure and bonding in your answer

Answer 33

- graphite is a giant covalent structure - graphite is arranged in layers that can slide over each other therefore it is soft - each carbon has bonded to 3 others - therefore there are delocalised electrons that can move therefore it conducts electricity

Question 34

explain why a giant ionic lattice is an insulator when solid

Answer 34

ions are fixed in place in lettuces therefore ions can’t move

Question 35

explain why a giant ionic lattice is a conductor when molten or dissolved

Answer 35

ions are free to move when aqueous

Question 36

what types of elements form metallic bonds?

Answer 36

metals

Question 37

describe the bonding in a metallic bond

Answer 37

strong electrostatic attraction between the positive metal ions and delocalised electrons

Question 38

is a metallic lattice a conductor, explain why

Answer 38

yes - delocalised electrons are free to move

Question 39

is a metallic lattice malleable, explain why

Answer 39

yes - layers/rows of (positive) ions can slide over each other (therefore they are ductile and can be pulled into wires)

Question 40

define an alloy

Answer 40

a MIXTURE of a METAL and ANOTHER ELEMENT

Question 41

alloys are harder than pure metals because:

Answer 41

- different sized atom - disrupts layers/rows of ions - therefore can’t slide over each other

Question 42

alloys are harder than pure metals, refer to the structure of both metals to explain why

Answer 42

- pure metals are soft - layers can slide over each other - alloys always contain another atom/element that is a different size - which disrupts the regular structure - therefore layers cannot easily slide over each other

Question 43

what types of elements form covalent bonds?

Answer 43

non-metals

Question 44

explain why simple molecular structures are insulators

Answer 44

no delocalised electrons or ions (particles are not charged)

Question 45

explain why ionic lattice are insulators when solid

Answer 45

- ions are not free to move

Question 46

explain why ionic lattice are conductors when liquid or aqueous

Answer 46

bonds break therefore ions are free to move

Question 47

what can a metal do that other elements can’t do when solid

Answer 47

conduct electricity

Question 48

is the melting point high or low in a giant ionic

Answer 48

high

Question 49

is the melting point high or low in a giant covalent

Answer 49

high

Question 50

is the melting point high or low in a simple molecular

Answer 50

low

Question 51

is a giant ionic soluble in water

Answer 51

usually yes

Question 52

is a giant covalent soluble in water

Answer 52

no

Question 53

is a simple molecular soluble in water

Answer 53

usually no

Question 54

can a giant ionic conduct electricity

Answer 54

only when molten or dissolved/aqueous

Question 55

can a giant covalent conduct electricity

Answer 55

only graphite

Question 56

can a simple molecular conduct electricity

Answer 56

NO

Question 57

graphite is a naturally occurring form of carbon explain why graphite is soft and conducts electricity refer to structure and bonding in your answer

Answer 57

- graphite is a giant covalent substance - soft -> arranged in layers -> that can slide over each other - conduct electricity -> each carbon atom is bonded to 3 others -> therefore it has delocalised electrons -> which are free to move

Question 58

the boiling point for fluorine, chlorine and bromine increase in temperature, explain the trend in boiling points

Answer 58

- boiling point increases - they are simple molecules so have weak intermolecular forces - down the group, the intermolecular forces get stronger and require more energy to overcome because the molecules get bigger

Question 59

explain why diamond has a much higher melting point in C60 fullerene refer to structure and bonding in your answer (5marks)

Answer 59

diamond: -> giant covalent structure -> lots of strong covalent bonds -> require immense energy to overcome C60 fullerene: -> simple molecule -> therefore it has weak intermolecular forces -> which require less energy to overcome