Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Edexcel Chemistry Flashcards > topic 4: inorganic chemistry and the periodic table > Flashcards

topic 4: inorganic chemistry and the periodic table Flashcards

(69 cards)

Start Studying
1
Q

what happens to the atomic radius down group 2

A

increases because one goes down the group, the atoms have more shells of electrons making the atom bigger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what happens to the melting point down group 2

A

down the group the melting points decrease
- the metallic bonding weakens as the atomic size
increases
- the distance between the positive ions and delocalized electrons increases
- therefore the electrostatic attractive forces between the positive ions and the delocalized electrons weaken

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what happens to the 1st ionisation energy down group 2

A

the outermost electrons are held more weakly because they are successively further from the nucleus in additional shells. in addition, the outer shell electrons become more shielded from the attraction of the nucleus by the
repulsive force of inner shell electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what happens to the reactivity down group 2 and why

A

the reactivity increases down the group as the atomic radii increase
- there is more shielding
- the nuclear attraction decreases and it is easier to remove (outer) electrons and so cations form more easily
- first ionisation energy decreases
- there is a increase in repulsion between the filled inner shells and the electrons removed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

group 2 + oxygen

A

the group 2 metals will burn in oxygen. Mg burns with a bright white flame
2Mg + O2 —> 2MgO
MgO is a white solid with a high melting point due to its ionic bonding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

group 2 + Cl2

A

The group 2 metals will react with chlorine
Mg + Cl2 —> MgCl2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Mg + steam

A

magnesium reacts in steam to produce magnesium oxide and hydrogen. the Mg would burn with a bright white flame
Mg (s) + H2O (g)  MgO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Mg + warm water

A

giving a different magnesium hydroxide product
Mg + 2 H2O  Mg(OH)2 + H2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

other group 2 + cold water

A

react with cold water with increasing vigour down the group to form hydroxides
Ca + 2H2O(l) —> Ca(OH)2(aq) + H2 (g)
Sr + 2H2O(l)—> Sr(OH)2(aq) + H2(g)
Ba + 2H2O(l) —> Ba(OH)2(aq) + H2(g)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

reactions of the oxides of group 2 elements with acids

A

MgO(s) + 2HCl(aq) —> MgCl2(aq) + H2O(l)
SrO(s) + 2HCl(aq) —> SrCl2(aq) + H2O(l)
CaO(s) + H2SO4(aq)  CaSO4(aq) + H2O(l)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

reactions of the hydroxides of group 2 elements with acids

A

2HNO3(aq) + Mg(OH)2(aq) —>Mg(NO3)2(aq) + 2H2O(l)
2HCl(aq) + Mg(OH)2(aq) —>MgCl2(aq) + 2H2O(l)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe the solubility of group 2 hydroxides

A

group II hydroxides become more soluble down the group. all Group II hydroxides when not soluble appear as white precipitates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

state the solubility of magnesium hydroxide

A

insoluble in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe solubility of calcium hydroxide

A

reasonably soluble in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe the solubility of barium hydroxide

A

easily dissolve in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

explain the solubility of group 2 sulfates

A

group 2 sulfates become less soluble down the group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

which group 2 sulfate is the least soluble

A

BaSO4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is thermal decomposition

A

the use of heat to break down a reactant into more than one product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

thermal decomposition of group 2 carbonates

A

group 2 carbonates decompose on heating to produce group 2 oxides and carbon dioxide gas
MgCO3(s) —> MgO(s) + CO2(g)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what happens to the group 2 carbonates thermal decomposition down the group

A

become more thermally stable going down the group. as the cations get bigger they have less of a polarising effect and distort the carbonate ion less. the C-O
bond is weakened less so it less easily breaks down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what happens to the group 1 carbonates thermal decomposition

A

group 1 carbonates do not decompose with the exception of lithium. as they only have +1 charges they don’t have a big enough charge density to polarise the carbonate ion. lithium is the exception because its ion is small enough to have a polarising effect
Li2CO3(s) —> Li2O(s) + CO2(g)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

test for thermal decomposition of carbonates

A

one is to heat a known mass of carbonate in a side arm boiling tube and pass the gas produced through lime water. time for the first permanent cloudiness to appear in the limewater. repeat for different carbonates using the same moles of carbonate/same volume of limewater/same Bunsen flame and height of tube above flame

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

thermal decomposition of group 2 nitrates

A

group 2 nitrates decompose on heating to produce group
2 oxides, oxygen and nitrogen dioxide gas. you would observe brown gas evolving (NO2) and the
white nitrate solid is seen to melt to a colourless solution and then re-solidify
2Mg(NO3)2 → 2MgO + 4NO2 + O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

describe the ease if thermal decomposition down the group

A

decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
why does magnesium nitrate decompose the easiest
because the Mg2+ ion is smallest and has the greater charge density. it causes more polarisation of the nitrate anion and weakens the N―O bond
26
thermal decomposition of group 1 nitrates
group 1 nitrates, with the exception of lithium nitrate, do not decompose in the same way as group 2 nitrates. they decompose to give a nitrate (III) salt and oxygen 2NaNO3 → 2NaNO2 + O2 4LiNO3 → 2Li2O + 4NO2 + O2
27
what is the method of a flame test
use a nichrome wire ( nichrome is an unreactive metal and will not give out any flame colour). clean the wire by dipping in concentrated hydrochloric acid and then heating in blue roaring Bunsen flame. if the sample is not powdered then grind it up. dip wire in solid and put in blue roaring Bunsen flame and observe flame
28
what is the explanation for the occurrence of flame
in a flame test the heat causes the electron to move to a higher energy level. the electron is unstable at the higher energy level and so drops back down. as it drops back down from the higher to a lower energy level, energy is emitted in the form of visible light energy with the wavelength of the observed light
29
what is the colour of lithium
scarlet red
30
what is the colour of sodium
yellow
31
what is the colour of potassium
lilac
32
what is the colour of rubidium
red
33
what is the colour of caesium
blue
34
what is the colour of magnesium
no flame colour
35
what is the colour of calcium
brick red
36
what is the colour of strontium
red
37
what is the colour of barium
apple green
38
describe the characteristics of fluorine (F2)
very pale yellow gas it is highly reactive
39
describe the characteristics of chlorine (Cl2)
greenish reactive gas poisonous in high concentrations
40
describe the characteristics of bromine (Br2)
red liquid that gives off dense brown/orange poisonous fumes
41
describe the characteristics of iodine (I2)
shiny grey solid sublimes to purple gas
42
describe the trend in melting and boiling point of halogens (group 7) and why
increase down the group as the molecules become larger they have more electrons and so have larger London forces between the molecules. as the intermolecular forces get larger more energy has to be put into break the forces. this increases the melting and boiling points
43
describe the trend of electronegativity for halogens
as one goes down the group the electronegativity of the elements decreases. as one goes down the group the atomic radii increases due to the increasing number of shells. the nucleus is therefore less able to attract the bonding pair of electrons
44
describe the reactivity of halogens
decreases down the group as the atoms get bigger with more shielding so they less easily attract and accept electrons. they therefore form -1 ions less easily down the group
45
what would chlorine displace
bromine and iodine
46
what does bromine displace
iodine
47
what does iodine displace
none
48
what are the different colour of the solution in the test tube which free halogen is present in solution
chlorine =very pale green solution (often colourless) bromine = yellow solution iodine = brown solution
49
what is the colour of the organic solvent layer in the test tube shows when each free halogen is present in solution
chlorine = colourless bromine = yellow iodine = purple
50
reaction of halogens with cold dilute NaOH solution
Cl2(aq) + 2NaOH(aq) ---> NaCl (aq) + NaClO (aq) + H2O(l) the mixture of NaCl and NaClO is used as bleach and to disinfect/ kill bacteria
51
reaction of halogens with hot dilute NaOH solution
3Cl2 (aq) + 6NaOH(aq) ---> 5 NaCl (aq) + NaClO3 (aq) + 3H2O (l)
52
what is the explanation of differing reducing power of halides
a reducing agent donates electrons. the reducing power of the halides increases down group 7. they have a greater tendency to donate electrons because as the ions get bigger it is easier for the outer electrons to be given away as the pull from the nucleus on them becomes smaller
53
what happens in the reaction between chloride/fluoride ions and H2SO4
The H2SO4 is not strong enough an oxidising reagent to oxidise the chloride and fluoride ions. no redox reactions occur. only acid - base reactions occur NaF(s) + H2SO4(l) --->NaHSO4(s) + HF(g) observations: white steamy fumes of HF are evolved NaCl(s) + H2SO4(l) NaHSO4(s) + HCl(g) observations: white steamy fumes of HCl are evolved
54
describe the reaction between bromide and H2SO4
stronger reducing agents than Cl- and F- and after the initial acid- base reaction reduce the sulfur in H2SO4 from +6 to + 4 in SO2 observations: white steamy fumes of HBr are evolved. red fumes of bromine are also evolved and a colourless, acidic gas SO2
55
what is the reaction between iodide and H2SO4
the strongest halide reducing agents. they can reduce the sulfur from +6 in H2SO4 to + 4 in SO2 , to 0 in S and -2 in H2S NaI(s) + H2SO4(l) ---> NaHSO4(s) + HI(g) 2HI + H2SO4 ---> I2(s) + SO2(g) + 2H2O(l) 6HI + H2SO4 ---> 3I2 + S(s) + 4H2O (l) 8HI + H2SO4 4I2(s) + H2S(g) + 4H2O(l) observations: white steamy fumes of HI are evolved. black solid and purple fumes of Iodine are also evolved. a colourless, acidic gas SO2. a yellow solid of Sulphur H2S (Hydrogen Sulphide), a gas with a bad egg smell
56
what is the test to identify the halide ions
nitric acid and silver nitrate solution
57
what is the role of nitric acid in the test of identifying halide ions
to react with any carbonates present to prevent formation of the precipitate Ag2CO3. this would mask the desired observations 2HNO3 + Na2CO3 ---> 2NaNO3 + H2O + CO2
58
what is the colour of the precipitate of the different halide ions
fluorides produce no precipitate chlorides produce a white precipitate Ag+(aq) + Cl-(aq) ---> AgCl(s) bromides produce a cream precipitate Ag+(aq) + Br-(aq) ---> AgBr(s) iodides produce a pale yellow precipitate Ag+(aq) + I-(aq) ---> AgI(s)
59
what is the effect of ammonia on silver halides
the silver halide precipitates can be treated with ammonia solution to help differentiate between them if the colours look similar
60
what does silver chloride dissolve in
dissolves in dilute ammonia to form a complex ion AgCl(s) + 2NH3 (aq) [Ag(NH3)2]+ (aq) + Cl- (aq) complex ion=colourless solution
61
what does silver bromine dissolve in
dissolves in concentrated ammonia to form a complex ion AgBr(s) + 2NH3(aq) [Ag(NH3)2]+(aq) + Br -(aq) complex ions =colourless solution
62
what does silver iodide dissolve in
does not react with ammonia – it is too insoluble
63
how are hydrogen halides produced and what is the observation
made by the reaction of solid sodium halide salts with phosphoric acid NaCl(s) + H3PO4(l)  NaH2PO4(s) + HCl(g) Observations: White steamy fumes of the hydrogen halides are evolved. the steamy fumes of HCl are produced when the HCl meets the air because it dissolves in the moisture in the air
64
what is the test for carbonate and hydrogencarbonate ions
add any dilute acid and observe effervescence. bubble gas through limewater to test for CO2 – will turn limewater cloudy. fizzing due to CO2 would be observed if a carbonate or a hydrogencarbonate was present
65
what is the test for presence of a sulfate
acidified BaCl2 solution is used as a reagent to test for sulfate ions. if barium chloride is added to a solution that contains sulfate ions a white precipitate forms Ba2+(aq) + SO42-(aq) ---> BaSO4(s)
66
what is the test for cations
test for ammonium ion NH4+, by reaction with warm NaOH(aq) forming NH3 NH4+ +OH- ---> NH3 + H2O
67
what is the test for ammonia gas
ammonia gas can be identified by its pungent smell or by turning damp red litmus paper blue
68
solubility in water of halogen halide
the hydrogen halides are all soluble in water. they dissolve to form acidic solutions HCl(g)+ H2O(l) ---> H3O+(aq)+ Cl-(aq)
69
what happens when hydrogen halides react with ammonia
the white smoke of the ammonium halide HCl(g) + NH3(g) ---> NH4Cl (s) HBr(g) + NH3(g) ---> NH4Br (s) HI(g) + NH3(g) ---> NH4I(s) this can be used as a test for the presence of hydrogen halides

Edexcel Chemistry Flashcards (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions