module 3 section 1 - The periodic table

Question 1

describe how atomic radius vary across a period (4)

Answer 1

• decrease
• nuclear charge increases
• no change in shielding
• greater attraction between nuc and outer shell

Question 2

describe how electronegativity varies across a period (4)

Answer 2

• increases
• nuclear charge increases
• no change in shielding
• greater attraction between nuc and outer shell

Question 3

describe how first ionisation energy varies across a period (4)

Answer 3

• increases
• nuclear charge increases
• no change in shielding
• greater attraction between nuc and outer shell

Question 4

describe the general structure and forces of group 1,2 and 3 elements in period 2 and 3 (4)

Answer 4

• giant metallic lattices
• lattice structures
• delocalised e-
• very strong electrostatic forces OA between cations and sea of delocalised e-

Question 5

how are giant metallic latices kept in a neatly arranged lattice ? (1)

Answer 5

• positively charged cations repel

Question 6

describe the structure and forces of group 4 elements in period 2 and 3 (2)

Answer 6

• giant covalent lattices
• strong electrostatic attraction between bonded electrons and nuclei of bonded atoms

Question 7

describe the structure and forces of group 5,6,7 and 0 elements in periods 2 and 3 (3)

Answer 7

• smell mlcls
• finite mlcls
• weak IDDI between mlcls

Question 8

state the properties of giant metallic lattices (5)

Answer 8

• malleable
• ductile
• high MP + BP
• insoluble
• good conductors of electricity

Question 9

explain how giant metallic lattices are malleable (2)

Answer 9

• layers can slide over eachother w out breaking bond
• can be bent into shape

Question 10

explain how giat metallic lattice are ductile (1)

Answer 10

layers can be pulles into wire, 1 atom thick

Question 11

explain why giant metallic lattices have high MP and BP (3)

Answer 11

• alot energy needed to overcome
• strong electrostatic of attraction]
• between cations and sea of delocalised e-

Question 12

explain the solubility of giant metallic lattices (2)

Answer 12

• not soluble
• interactions between polar mlcls and metallic lattice more likely to lead to reactions

Question 13

explain the conductivity of giant metallic lattices (3)

Answer 13

• good conductors of electricity as molten and solid
• delocalised e- move and carry charge
• throughout whole structure

Question 14

describe the structure of the element boron (3)

Answer 14

• semi metal ( metalloid )
• semi conductor
• similar structure to carbon and silicon

Question 15

state the properties of giant covalent lattices (3)

Answer 15

• insoluble
• do not conduct electricity
• high MP and BP

Question 16

why do giant covalent lattices not conduct electricity (1)

Answer 16

• no delocalised e- or mobile ions

Question 17

why do giant covalent lattices have a high MP + BP (3)

Answer 17

• very srong attractive forces
• between nuclei and shared pair of e-
• alot energy needed to overcome

Question 18

state 4 examples of giant covalent lattices

Answer 18

• diamond
• graphite
• graphene
• silicon oxide

Question 19

state the properties of simple covalent mlcls (2)

Answer 19

• dont conduct electricity
• low MP and BP

Question 20

explain why simple covalent mlcls do not conduct electricity (1)

Answer 20

• no deolcalised e- or mobile ions

Question 21

explain why simple cov mlcls have low MP and BP (2)

Answer 21

• weak IDDI between mlcls
• dont need much energy to overcome

Question 22

name 2 multiatomic mlcls and state their formula (2)

Answer 22

phosphorous - P4
sulfur - S8

Question 23

state 2 monoatomic mlcls (2)

Answer 23

• neon
• argon

Question 24

how does BP and MP vary along group5,6,7,8 elements ?

Answer 24

• larger mlcl = more e- = higher MP + BP

Question 25

does sulfur or chlorine have a higher MP ? (3)

Answer 25

- sulfur - S8 = 16 X 8 = 128e-'s - Cl2 = 17 X 2 = 34 e-

Question 26

explain why lithium is an S-block element (1)

Answer 26

- outermost electron is in an S - orbital

Question 27

suggest why group 1 metals are called alkali metals give examples to justify your answer (3)

Answer 27

- they react with water to form alkaline solutions - 2Na(s) + H2O (l) = 2NaOH(aq) + H2 (g) - 2K (s) + H2O (l) = 2KOH (aq) + H2 (g)

Question 28

describe periodicity along a period (3)

Answer 28

- atomic number increases - same number of shells - atomic radium decreases

Question 29

describe periodicity down a group (2)

Answer 29

- similar outer shell electron configuration - similar chem and physical properties

Question 30

state what determins the order of elemnts in the periodic table (1)

Answer 30

atomic number

Question 31

describe the trend in atomic radius across a period (4)

Answer 31

- atomic radius decreases - as number of protons ( stomic no.) increases - nuclear charge increases - attraction between nuc + outermost e- increases

Question 32

identify 3 elements that will have an electron configuration ending with d3 (3)

Answer 32

- vanadium - niobium - tantalum

Question 33

justify the position of the d - block in the periodic table (2)

Answer 33

- 3d subshell higher in energy than 4s subshell - but lower in energy than 4p subshell

Question 34

what makes hydrogen not fit group 1 ? (4)

Answer 34

- doesnt conduct heat/ electricity - very low BP - doesnt form cations readily - forms mostly cov bonds

Question 35

what makes hydrogen fit group 1 ? (1)

Answer 35

- outer shell configuration contains 1 s-orbital electron only

Question 36

what makes helium fit group 0 ? (5)

Answer 36

- monoatomic - very low MP + BP - gas at RTP - inert - full outer shell configuration

Question 37

what makes helium not fit group 0 ? (1)

Answer 37

- outer shell configuration contains 2 s-orbital electrons only ( no P subshell)

Question 38

describe and explain the trends in electronegativity for Li - Fr (4)

Answer 38

- decreases - atomic radius increases - increased sheilding - reduced nucelar attraction to outermost e-

Question 39

describe and explain trends in reactivity for Li - Fr (3)

Answer 39

- increases - reduced nuc attraction between nuc and outermost e- - form cations more readily

Question 40

suggest why hydrogen have a higher electronegativity than lithium (3)

Answer 40

- only has 1 e- - no e- sheilding - nuc charge is stroger

Question 41

suggest why hydrogen forms covalent bonds (1)

Answer 41

- smaller diff in electroneg between hydrogen and other metals (<1.8)

Question 42

suggest why hydrogen is a gas at RTP (3)

Answer 42

- hydrogen exists as small mlcls - IDDI between mlcls are weak - little energy needed to overcome

Question 43

give a chemical explanation for why potassium is placed immediately after argon in the periodic table (1)

Answer 43

- potassium atoms have 1 more proton than argon

Question 44

suggest and justify wether oxygen or nitrogen would have a lower first ionisation energy (2)

Answer 44

- oxygen - repulsion from paired electrons in 2p subshell make it easier to remove an e- in an ox atom

Question 45

write the equation for 1st ionisation energy

Answer 45

A(g) = A+(g) + e-

Question 46

write an equation for the first ionisation energy of sodium (1)

Answer 46

Na(g) = Na+ (g) + e-

Question 47

write and equation for the first ionisation energy of oxygen (1)

Answer 47

O (g) = O+ (g) + e-

Question 48

describe the trend in 1st ionisation energy down a group (4)

Answer 48

- decreases - increased sheilding - decreased nuc attraction between nuc and outermost e- - easier to remove an e-

Question 49

describe the trend in first ionisation energy along a period (5)

Answer 49

- generally increases - decreased atomic radius - same number of shells - increased nuc charge - increased nuc attraction between nuc and outermost -

Question 50

what do large jumps in ionisation energy show (1)

Answer 50

evidence for change in shell

Question 51

what do small jumps in ionisation energy show (1)

Answer 51

evidence for change in sub shell

Question 52

write an equation for 2nd ionisation energy (1)

Answer 52

A+(g) = A2+ (g) + e-

Question 53

write an equation for 3rd ionisation energy (1)

Answer 53

A2+ (g) = A3+ (g) + e-

Question 54

explain why successive ionisation energies increase (4)

Answer 54

- nuc attraction shared between all e- in the shell - e- removed but no change to nuc charge - slightly greater attraction between nuc and outermost e- - more energy needed to overcome

Question 55

describe the trend in successive ionisation energies (2)

Answer 55

- increase as more e- are removed - increase is not constant

Question 56

what does the increase in successive ionisation energies depend on (1)

Answer 56

electron configuration

Question 57

what 3 factors affect ionisation energy (3)

Answer 57

- atomic radius - nuclear charge - electrons shielding

Question 58

explain how atomic radius affects first ionisation energy (3)

Answer 58

- larger atomic radius = - weaker attraction between nuc and outermost e- - = lower ionisation energy

Question 59

explain how nuclear charge affects ionisation energy (4)

Answer 59

- increased no. protons - greater nuc charge - harder to remove an e- - higher ionisation energy

Question 60

explain how electron ehilding affects ionisation energy (4)

Answer 60

- increased shielding - reduced attraction between nuc and outermost e- - easier to remove an e- - lower ionisation energy

Question 61

compare the first ionisation energies of berylium and boron (4)

Answer 61

- highest energy e- in boron is in a 2p subshell - in berylium it is in a 2 s subshell - 2p subshell in boron has higher energy than 2s subshell in berylium - 2p electron in boron easier to remove than 2 s e-'s in berylium - 1st IE in boron is less than in berylium

Question 62

compare the 1st IE of nitrogen and oxygen (4)

Answer 62

- in nit + ox highest energy e-'s are in a 2p subshell - in ox the paired e-'s in one of the 2p orbitals repel - easier to remove an e- from oxygen atom than nit atom - first IE of ox = less

Question 63

what are group 2 metals commonly used as ? (1)

Answer 63

reducing agents

Question 64

which group 2 element would be the best reducing agent, explain why (6)

Answer 64

- radium - more shells - more sheilding - wekaer nuc charge - weaker attraction between nuc + outermost e- - forms cations more readily

Question 65

describe the trend of reactivity going down group 2 (2)

Answer 65

- reactivity increases - as cations form more readily

Question 66

state trhe key trends which occur going down group 2 (2)

Answer 66

- 1st and 2nd IE decrease - reactivity increases

Question 67

write a general equation for the reaction of group 2 metals with oxygen (2)

Answer 67

M(s) + O2 (g) = 2MO (s)

Question 68

write a balanced symbol equation for the reaction of magnesium with oxygen (2)

Answer 68

Mg(s) + O2 (g) = 2 MgO (s)

Question 69

write a balanced symbol equation for the reaction of berylium with oxygen (2)

Answer 69

Be(s) + O2 (g) = 2BeO (s)

Question 70

write the general formula for the reaction of group 2 metals with water (2)

Answer 70

M (s) + 2H2O (l) = M(OH)2 (s) + H2 (g)

Question 71

what observations can be made during the reaction of a group 2 metal with water ? (2)

Answer 71

- effervescence - alkaline solution

Question 72

describe the reaction of beryllium with water (1)

Answer 72

no reaction with water

Question 73

describe the reaction of magnesium with water (2)

Answer 73

- very slow reaction w water - vigorous reaction w steam but produces MgO

Question 74

what 2 reagents can be reacted with magnesium to produce magnesiuym oxide ? (2)

Answer 74

- oxygen - steam

Question 75

explain with equations the differences in chemistry and observations between the reactions of magnesium with water and steam (6)

Answer 75

- water: Mg (s) + 2H2O (l) = Mg(OH)2 (s) + H2 (g) - very slow reaction - slight effervescence produced - hydroxide produced - alkaline solution ( around 10) - steam: Mg(s) + H2O(g) = MgO (s) + H2 (g) - fast reaction - faster effervescence from H2 produced - MgO produced - no alkaline solution

Question 76

write the general equation for the reaction of group 2 metals with dilute acids (2)

Answer 76

M (s) + 2HX (aq) = MX2 (aq) + H2 (g)

Question 77

explain why observations would be different when magnesium reacted with sulfuric acid compared to barium (6)

Answer 77

- Mg (s) + H2SO4 (aq) + MgSO4 (aq) + H2 - colourless solution of magnesium sulfate formed - as magnesium sulfate in soluble - Ba (s) + H2SOO4 (aq) = BaSO4 (s) + H2 (g) - white precipitate of barium sulfate formed - bcs barium sulfate is insoluble

Question 78

describe solubility of group 2 carbonates as you move down group 2 (1)

Answer 78

solubility decreases ( become insoluble)

Question 79

describe the solubility of group 2 hydroxides in water as you move down group 2 (1)

Answer 79

increases

Question 80

describe how group 2 oxides react with water (4)

Answer 80

- release hydroxide ions - forming an alkaline solution - higher conc of OH- ions = more alkaline solution - so solution gets more alkalne down group

Question 81

write the ionic equation for a group 2 oxide reacting with water

Answer 81

MO (s) + H2O (l) = M2+ (aq) + 2OH- (aq)

Question 82

explain why solutions produced by group 2 metal oxides reacting with water increase in alkilinity as you move down group 2 (3)

Answer 82

- greater solubility of metal hydroxides - more OH- ions released - group 2 hydroxides become more soluble down group

Question 83

describe the use of Mg(OH)2 refering to its PH and solubility (3)

Answer 83

- PH10 - partially soluble in water - used to neutralise stomach acid

Question 84

which alternative metal carbonate can be used to neutralise stomach acid ? (1)

Answer 84

CaCO3

Question 85

describe what Ca(OH)2 is used for referring to its PH and solubility (3)

Answer 85

- PH 11 - resonably soluble in water - used in agriculture to neutralise acidic soil

Question 86

describe the trend in solubility of group 2 sulfates down the group (1)

Answer 86

- become less soluble down the group

Question 87

explain the trnd in PH of each hydroxide solution down the group 2 (3)

Answer 87

- greater solubility of group 2 metal hydroxides - greater conc of OH- ions released - increased alkalinity = higher PH

Question 88

suggest a reason for the trend in solubility going down group 2 metal hydroxides (5)

Answer 88

- solubility increases - cations increase in size - increased electropositivity - increased ionic character - decrease in lattice enthalpy ( strength between cations + OH anions)

Question 89

what is thermal decomposition ? (3)

Answer 89

- the breakdown of a compound - into 2 or more different substances - using heat

Question 90

write the general equation for thermal decomposition (1)

Answer 90

MCO3 (s) = MO(s) + CO2 (g)

Question 91

describe and explain when the heat energy needed for the thermal decomposition of a group 2 metal carbonate decreases (4)

Answer 91

- greater charge density of metal ion - more polarised carbonate ion becomes - greater polarisation - less heat needed to break C- O bond

Question 92

describe the trend in charge density as you go down group 2 metal ions (3)

Answer 92

- decreases - charge remains 2+ - atomic radius increases

Question 93

what will have a higher charge density, berylium or magnesium ? (1)

Answer 93

berylium

Question 94

what does a high charge density mean in terms of thermal stability ? (1)

Answer 94

low thermal stability

Question 95

describe the trend in energy needed for thermal decomposition going down group two metal carbonates (6)

Answer 95

- energy increases - as charge density decreases - thermal stability increases - carbonate ion becomes less polarised - less polarisation - more enrgy needed to overcome C - O bond

Question 96

give the formula of magnesium carbonate (1)

Answer 96

MgCO3(s)

Question 97

predict the group 2 nitrate that would require the least energy to thermally decompose

Answer 97

Be(NO3)2

Question 98

explain why magnesium carbonate is less thermally stable that calcium carbonate (4)

Answer 98

- Mg ion has a higher charge density than Ca ion - as has less sheilding but same nuc charge - able to polarise carbonate ion - breaking C - O bond

Question 99

compare the thermal stability of sodium carbonate with magnesium carbonate (2)

Answer 99

- sodium carbonate more thermally stable - as sodium ion has lower charge density than Mg ion

Question 100

suggest why solutions need to be acidified before testing for sulfate ions using barium nitrate (3)

Answer 100

- remove any carbonate ions - if carbonate ions were prsent they would also form a white precipitate w barium ions - identical; in appearence as both insoluble

Question 101

state the type of reaction which takes place when barium reacts with oxygen to form barium oxide (1)

Answer 101

redox

Question 102

name the reagent that reacts with barium oxide to form barium hydroxide, state the type of reaction it is and write out the equation (3)

Answer 102

- water - BaO (s) + H2O (l) = Ba(OH)2 (aq) - combination

Question 103

name the reagent that reacts with magnesium nitrite to form magnesium hydroxide, state the type of reaction it is and write out the equation (3)

Answer 103

- water - Mg3N2 (aq) + 6H2O (g) = 3Mg(OH)2 (s) + 2NH3 (g) - displacement

Question 104

descrube and explain the trend reactivity of group 2 metals with water (4)

Answer 104

- reactivity increases down group - increased e- sheilding - no change in nuc charge - form cations more readily

Question 105

suggest why the reactions of Ca - Ba with sulfuric acid are slower than the reactions of Be or Mg (2)

Answer 105

- Ca - Ba form insoluble sulfates - formation of insoluble sulfate layer on metal surface prevents further reactions with acid

Question 106

what is the physical colour and state of fluorine ?

Answer 106

pale yellow gas

Question 107

what is the physical colour and state of chlorine ?

Answer 107

green gas

Question 108

what is the physical colour and state of bromine ?

Answer 108

red-brown liquid

Question 109

what is the physical colour and state of iodine ?

Answer 109

black solid

Question 110

describe the physical structure of halogen molecules (3)

Answer 110

- diatomic mlcls - weak IDDI between mlcls - simple mlclr structures

Question 111

what type of structures do halogen molecules form ? (1)

Answer 111

simple molecular structures

Question 112

describe the trend in boiling points down the halogens (5)

Answer 112

- increase down group - mlcl becomes larger - more e- - stronger IDD forces between mlcls - more energy needed to overcome IDD forces

Question 113

what type of molecules do halogens form at RTP ? (1)

Answer 113

diatomic molecules

Question 114

state the outer electron configuration of the halogens (1)

Answer 114

s2 p5

Question 115

describe the trend in reactivity going down the group 7 halogens (5)

Answer 115

- reactivity decreases down group - atomic radius increases - greater e- sheilding - less nuc attraction between nuc + outermost e- - forms anions less readily

Question 116

descfribe what happend during a displacment reaction (1)

Answer 116

a more reactive halogen displaces a less reactive halogen

Question 117

write an ionic equation to show chlorine displacing bromide ions

Answer 117

Cl2(aq) + 2Br- (aq) = Br2 (aq) + 2Cl- (aq)

Question 118

justify using ionic equations and oxidation numbers a halogen that could be used to reduce aqeuous sodium bromate (V) to bromine. (6)

Answer 118

- I2 (aq) + 2BrO- 3 (aq) = Br2 (aq) + 2IO3 - (aq) - I went from 0 to +5 = oxidised - Br went from +5 to 0 = reduced - iodine will reduce bromate (V) at it is a stronger reducing agent - due to greater nuc shielding - so less attraction to outer e-

Question 119

state the polarity of organic layers in displacement observations

Answer 119

non polar

Question 120

state the polarity of aqueous layers in displacement observations

Answer 120

polar

Question 121

dscribe how you are able to identify between polar and non polar solvents in a displacement observation (2)

Answer 121

- polar and non polar solvents are immiscible - form seperate phases

Question 122

describe how you are able to distinguish between a halogen and a halide during a displacement observation (2)

Answer 122

- non polar halogen will dissolve in non polar organic layer - polar halide will dissolve in polar aqueous layer

Question 123

describe the state and appearence of chlorine in water (2)

Answer 123

pale green solution

Question 124

describe the state and appearence of bromine in water (2)

Answer 124

orange solution

Question 125

describe the state and appearence of iodine in water (2)

Answer 125

brown solution

Question 126

state the obervation reaction and equation which occurs when potassium chloride (aq) reacts with chlorine (aq) (3)

Answer 126

- green solution - no reaction

Question 127

state the obervation reaction and equation which occurs when potassium chloride (aq) reacts with bromine (aq) (3)

Answer 127

- yellow/ orange solution - no reaction

Question 128

state the obervation reaction and equation which occurs when potassium chloride (aq) reacts with iodine (aq) (3)

Answer 128

- brown solution - no reaction

Question 129

state the obervation reaction and equation which occurs when potassium bromide (aq) reacts with chlorine (aq) (3)

Answer 129

- yellow / orange solution - cl displaced Br - Cl2 (aq) + 2Br- (aq) = Br2 (aq) + 2Cl- (aq)

Question 130

state the obervation reaction and equation which occurs when potassium bromide (aq) reacts with bromine (aq) (3)

Answer 130

- yellow / orange solution - no reaction

Question 131

state the obervation reaction and equation which occurs when potassium bromide (aq) reacts with iodine (aq) (3)

Answer 131

- brown solution - no reaction

Question 132

state the obervation reaction and equation which occurs when potassium iodide (aq) reacts with chlorine (aq) (3)

Answer 132

- brown solution - cl displaces I - Cl2 (aq) + 2I- (aq) = I2 (aq) + 2Cl- (aq)

Question 133

state the obervation reaction and equation which occurs when potassium iodide (aq) reacts with chlorine (aq) (3)

Answer 133

- Cl2 (aq) + 2Br- (aq) = Br2 (aq) + 2Cl- (aq)

Question 134

state the obervation reaction and equation which occurs when potassium iodide (aq) reacts with bromine (aq) (3)

Answer 134

- brown solution - Br displaces I - Br2 (aq) + 2I- (aq) = I2 (aq) + 2Br- (aq)

Question 135

state the obervation reaction and equation which occurs when potassium iodide (aq) reacts with iodine(aq) (3)

Answer 135

- brown solution - no reaction

Question 136

what colour is chlorine in non polar solvents such as hexane (1)

Answer 136

pale yellow - green

Question 137

what colour is bromine in non polar solvents such as hexane (1)

Answer 137

yellow - orange

Question 138

what colour is iodine in non polar solvents such as hexane (1)

Answer 138

purple

Question 139

explain how you can use a displacement reaction to identify organic and aqueous layers (4)

Answer 139

- use a seperating funnel - shake hexane w dilute aqueous halide solution - 2 layers form - aqueous + organic - organic on top

Question 140

sodium iodid is shaken with bromine, describe the clours of each layer and explain using an ionic equation what this shows (4)

Answer 140

- organic layer: purple - aqueous layer: orange - Br2 (aq) + 2I- (aq) = I2 (aq) + 2Br- (aq) - iodine displaced by bromine

Question 141

sodium bromide is shaken with chlorine, describe the clours of each layer and explain using an ionic equation what this shows (4)

Answer 141

- organic layer: orange/layer - aqueous layer: pale green/colourless - Cl2 (aq) + 2Br- (aq) = Br2 (aq) + 2Cl- (aq) - bromine displaced by chlorine

Question 142

sodium chloride is shaken with iodine, describe the clours of each layer and explain using an ionic equation what this shows (4)

Answer 142

- organic layer: pale yellow - green - aqusous layer : brown - no reaction between iodine ad sodium chloride

Question 143

Solutions such as iodine and bromine can appeara similar orange colour depending on concentration explain what can be done to tell them apart (2)

Answer 143

• Add cyclohexane to shaken mixture • non polar halogen dissolves more readily un cyclohexane than water

Question 144

What colour is chlorine in cyclohexane

Answer 144

Pale green

Question 145

What colour is bromine in cyclohexane

Answer 145

Orange

Question 146

What colour is iodine incyclohexane

Answer 146

Violet

Question 147

Which halogen is the strongest oxidising agent?

Answer 147

Fluorine

Question 148

What can caloric acid act as

Answer 148

A weak bleach

Question 149

How can you demonstrate that caloric acid acts as a weak bleach (3)

Answer 149

• Add indicator to solution of chlorine in water • indicator first turns red • then colour disappears because of bleaching effect

Question 150

Write the equation for the reaction of chlorine with water, what are the 2 products

Answer 150

CL2 (aq) + H2O(l) = HClO (aq) + HCl(aq) - chloric acid - hydrochloric acid

Question 151

Explain why the reaction of chlorine water is limited (1)

Answer 151

- Because of low solubility of chlorine in water

Question 152

Describe a reaction which produces more chlorate ions , Cl o -)than is produced when chlorine reacts with water (5)a

Answer 152

-Chlorine with cold dilute aqueous sodium hydroxide - - much more chlorine dissolves CL2(aq) + 2NAOH(aq) = NaClO(aq) + NaCl(aq)+ H2O (l) - disproportination reaction - resulting solution contains a large concentration of chlorate sons from sodium chlorate

Question 153

what type of process is ionisation ? (1)

Answer 153

endothermic

Question 154

ionisation energy decreases when going down a group, what does this act as evidence for ? (2)

Answer 154

- shells exist - supports Bohr model of the atom

Question 155

explain why there is a drop in ionisation energy going from group 2 to group 3 (5)

Answer 155

- change in subshell - outer e- in group 3 elements in p subshell but group 2 in s subshell - p orbital has a slightly higher energy - p orbital found further from nuc - p orbital has additional sheilding provided by s electrons | these p and s orbitals are found in the same shell

Question 156

explain why there is a drop in ionisation energy between group 5 and 6 (4)

Answer 156

- P orbital repulsion - in group 5 elements e- is removed from sngly occupied orbital - in group 6 elements an e- is being removed from orbital containing 2e- - repulsion between 2e- in orbital means e- are easier to remove

Question 157

what is an allotrope (3)

Answer 157

- diff forms - of same element - in same state

Question 158

name 3 allotropes of carbon (3)

Answer 158

- diamond - graphite - graphene

Question 159

how can carbon atoms is each carbon atom in diamond bonded to ? (1)

Answer 159

4

Question 160

state the shape which atoms arrange themselves into in a diamond (1)

Answer 160

tetrahedral

Question 161

state the properties of diamond (5)

Answer 161

- v high MP - v hard - good thermal conductor - cant conduct electricity - insoluble

Question 162

describe the covalent bonds in diamond (1)

Answer 162

lots of strong cov bonds

Question 163

state the properties of graphite (6)

Answer 163

- feels slippery - sheets can slide over eachother - conduct electricity - less dense than diamond - very high MP - insoluble

Question 164

describe the structure of graphite (4)

Answer 164

- C atoms aranged in sheets - each C atom forms 3 cov bonds - 4th e- is deolcalised between sheets - sheets bonded togtether by weak IDDI

Question 165

explain why graphite is slippery (2)

Answer 165

- weak IDDI between layers easily broken - so sheets can slide over eachother

Question 166

explain why graphite can conduct electricity (3)

Answer 166

- delocalised e- between sheets - mobile - free to move through full structure + carry elec charge

Question 167

explain why graphite is less dense than diamond (1)

Answer 167

layers far apart

Question 168

why does graphite have a high MP ? (1)

Answer 168

strong cov bonds

Question 169

explain why graphite is insoluble (1)

Answer 169

cov bonds in sheets too strong to break

Question 170

state 3 uses of graphite (3)

Answer 170

- dry lubricant - in pencils - strong, lightweight sports equipment

Question 171

what is graphene ? (1)

Answer 171

1 layer of graphite

Question 172

describe the structure of graphene (3)

Answer 172

- sheet of carbon atoms joined in hexagons - one atom thick - 2D cmpnd

Question 173

state the properties of graphene (3)

Answer 173

- best known electrical conductor - extremely strong - a single layer is transparent + v light

Question 174

why is graphene very strong ? (1)

Answer 174

- delocalised e- strengthen cov bonds between C atoms

Question 175

state 3 uses of graphene (3)

Answer 175

- high speed electronics - aircraft tehnology - touchscreens

Question 176

describe the MP and BP of ionically bonded mlcls

Answer 176

high

Question 177

describe the MP and BP of simple cov mlcls

Answer 177

low

Question 178

describe the MP and BP of giant cov lattices

Answer 178

high

Question 179

describe the MP and BP of giant metallic lattices

Answer 179

high

Question 180

describe the state of ionically bonded mlcls at RTP

Answer 180

solid

Question 181

describe the state of simple cov mlcls at RTP

Answer 181

sometimes solid but usually liquid or gas

Question 182

describe the state of giant cov lattices at RTP

Answer 182

solid

Question 183

describe the state of giant metallic lattices at RTP

Answer 183

solid

Question 184

do ionically bonded mlcls conduct electricity when solid ?

Answer 184

no

Question 185

do simple cov mlcls conduct electricity when solid ?

Answer 185

no

Question 186

do giant cov lattices conduct electricity when solid ?

Answer 186

no

Question 187

do giant metallic lattices conduct electricity when solid ?

Answer 187

yes

Question 188

do ionically bonded mlcls conduct electricity when liquid ?

Answer 188

yes

Question 189

do simple cov mlcls conduct electricity when liquid ?

Answer 189

no

Question 190

do giant cov lattices conduct electricity when liquid ?

Answer 190

will generally sublime

Question 191

do giant metallic lattices conduct electricity when liquid ?

Answer 191

yes

Question 192

are ionic mlcls soluble in water ?

Answer 192

yes

Question 193

are simple cov mlcls soluble in water ?

Answer 193

depends how polarised mlcl is

Question 194

are giant cov lattices soluble in water ?

Answer 194

no

Question 195

are giant metallic lattices soluble in water ?

Answer 195

no

Question 196

what products are formed when a group 2 metal reacts with water ? (2)

Answer 196

- metal hydroxide - hydrogen

Question 197

what products are formed when a group 2 metal burns in oxygen ? (1)

Answer 197

solid white oxide

Question 198

write the ionic equation for the reaction of calcium oxide with water

Answer 198

CaO(s) + H2O(l) = Ca2+ (aq) + 2OH-(aq)

Question 199

describe the reaction which occurs when group 2 oxides react with water (3)

Answer 199

- form metal hydroxides - whoch dissolve hydroxide ions - making solutions strongly alkaline

Question 200

what are group 2 compounds used for ? (1)

Answer 200

neutalise acidity

Question 201

which group 2 compoun d is used in agriculture to neutralise acidic soild ?

Answer 201

Ca(OH)2

Question 202

which group 2 comounds are used in indegestion tablets to neutralise stomach acids ? (2)

Answer 202

- Mg(OH)2 - CaCO3

Question 203

what type of molecules are halogen molecules ?

Answer 203

diatomic

Question 204

describe the trend in volatility moving down group 7 (1)

Answer 204

- decreases

Question 205

describe how bleach is made (2)

Answer 205

- mix chlorine gas with cold dilute aquesous sodium hydroxide - forming sodium chlorate ( bleach)

Question 206

write the equation for the formation of bleach

Answer 206

2NaOH (aq) + Cl2 (g) = NaClO(aq) + NaCl (aq) + H2O (l)

Question 207

explain how chlorine can be used to kill bacteria in water (5)

Answer 207

- mix chlorine w water - undergoes disproportiniation - form HCL + chloric acid - aquesous chloric acid ionises to ake chlorate ions - chlroate ions kill bacteria

Question 208

what is the physical state of fluorine ?

Answer 208

gas

Question 209

what is the physical state of chlorine ?

Answer 209

gas

Question 210

what is the physical state of bromine ?

Answer 210

liquid

Question 211

what is the physical state of iodine ?

Answer 211

solid

Question 212

what are the benefits to using chlorine for water treatements (5)

Answer 212

- kills disease causing microorganisms - some Cl stays in water and prevents reinfection - prevents growth of algae - eliminates bad taste + smell - removes discoloration cause by organic cmpnds

Question 213

what are the risks assosiated with using chlorine to treat water (3)

Answer 213

- Cl gas irritates resp system if breathed in - liq Cl causes chem burns - water contains many organic cmpnds and chlorine reacts w these cmpnds to form chlorinated hydrocarbons = carcinogenic

Question 214

what are some alternatives to using chlorine to treating water ? (2)

Answer 214

- ozone - ultraviolet light

Question 215

state some dissadvantages assosiated with using ozone to treat water (2)

Answer 215

- £££ to produce - short Half Life so treatement isnt permanent

Question 216

state some dissadvantages assosiated with using Ultraviolet light to treat water (2)

Answer 216

- innefective in cloudy water - water treatement not permanent

Question 217

how does UV light kill microorganisms ? (1)

Answer 217

damaging their DNA

Question 218

what is the formula for ozone ?

Answer 218

O3

Question 219

in what order should we test for ions ? (3)

Answer 219

- test for carbonates - test for sulfates - test for halides

Question 220

explain how you can test for carbonates (1)

Answer 220

- add dilute acid

Question 221

what will be present if a carbonate is present after adding dilute acid to your sample ? (1)

Answer 221

CO2 will be released

Question 222

write the equation for the reaction which occurs when testing for carbonates

Answer 222

CO3^2- (s) + 2H+(aq) = CO2(g) + H2O(l)

Question 223

write the equation for the reaction which takes place when dilute hydrochloric acid is added to calcium carbonate when testing for carbonates

Answer 223

CaCO3(s) + HCl(aq) = CO2(g) + H2O(l) + CaCl2(aq)

Question 224

explain how you can test for carbon dioxide (2)

Answer 224

- bubble gas through test tube of limewater - CO2 turns limewater cloudy

Question 225

explain how you can test for sulfate ions (4)

Answer 225

- add dilute HCl - followed by barium chloride solution - white ppt = barium sulfate - telling you a sulfate is present

Question 226

write the equation for the reaction which takes place when testing for sulfate ions

Answer 226

- Ba2+ (aq) + SO4^2- (aq) = BaSO4 (s)

Question 227

write the equation for the reaction which takes place when testing for sulfate ions in a solution of sodium sulfate

Answer 227

Na2SO4 (aq) + BaCl2 (aq) = BaSO4 (s) + 2 NaCl (aq)

Question 228

explain how you would test for halides (3)

Answer 228

- add nitric acid - then silver nitrate solution - if chloride, bromide or iodide present a ppt will form

Question 229

describe the ppt which will form if chloride ions are present (1)

Answer 229

white ppt

Question 230

describe the ppt which will form if bromide ions are present (1)

Answer 230

cream ppt

Question 231

describe the ppt which will form if iodide ions are present (1)

Answer 231

yellow ppt

Question 232

why wont silver fluoride give any ppt ? (1)

Answer 232

it is soluble

Question 233

how can you use ammonia to tell chloride, bromise and iodide ions apart ? (3)

Answer 233

- AgCl dissolves in dilut NH3 + conc NH3 - AgBr doesnt dissolve in dilute NH3 but dissolves in conc NH3 - AgI doesnt dissolve in either dilute or conc NH3

Question 234

explain how you can test for ammonia gas (3)

Answer 234

- ammonia gas = alkaline - use damp peice of red litmus paper - turns blue

Question 235

what is the formula for ammonia gas ? (1)

Answer 235

NH3

Question 236

what is the formula for ammonium ions (1)

Answer 236

NH4^+

Question 237

explain how you can test for ammonium ions (3)

Answer 237

- add some sodium hydroxide to substance in a test tube - warm mixture - if ammonia given off = ammonium ions present

Question 238

write the ionic equation for the reaction which takes place when testing for ammonium ions

Answer 238

NH4^+ (aq) + OH- (aq) = NH3 (g) + H2O (l)

Question 239

write the equation for the reaction which takes place when testing for ammonium ions in a sample of ammonium chloride

Answer 239

NH4Cl (aq) + NaOH (aq) = NH3 (g) + H2O (l) + NaCl (aq)

Question 240

why does the red litmus paper need to be damp when testing for ammonia ? (2)

Answer 240

- so ammonia gas can dissolve - and make colour change

Question 241

why do we add dilute acid first when testing for ions ? (1)

Answer 241

- remove any carbonate ions present - bcs barium carbonate is also a white ppt

Question 242

why doe we test for sulfate ions before testing for halide ions (1)

Answer 242

- silver sulfate would form - which is a white ppt

Question 243

how can we get around the issue of false positives when testing for carbonate ions, sulfate ions and halide ions ? (2)

Answer 243

- adding dilute acid first to test samples - to get rid of any unwanted anions

Question 244

why do we test for halides last ? (1)

Answer 244

- silver carbonate and silver sulfate are both white ppt