Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AQA Chemistry A level > Inorganic Chemistry > Flashcards

Inorganic Chemistry Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

3.2.1
What is the definition of periodicity?

A

It is the quality or character of being periodic; the tendency to recur at intervals

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

3.2.1
How is an element classified?

A

An element is classified as s,p,d,f block when the highest energy electrons are in an s,p,d,f sub-shell.

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

3.2.1
What are the 2 physical properties trends of period 3 elements?

A
  • Atomic radius
  • melting points
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

3.2.1
Why does atomic radius decrease across a period?

A

Atomic radius decreases across a period because…
* As the number of protons increase across the period, nuclear charge increase therefore stronger nuclear attraction.
* Therefore outer electrons (which are in the same level across the period) are drawn closer to the nucleus.

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

3.2.1
Why does the melting point across a period increase?

A

The m.p.s of metallic elements increase across the period.
* Na ➜ Al, number of outer electrons increase
* Therefore more electrons can be delocalised, leading to a greater attraction between positive ions and delocalised electrons.
* Size of ions decrease across the period, leading to smaller ions, and therefore greater attraction between positive ions and delocalised electrons.
* Therefore more energy required to overcome attraction

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

3.2.1
Why is the melting point of silicon very high?

A

The melting point of silicon is very high.
* Si has a giant covalent structure (compared to giant metallic for Na, Mg + Al).
* Therefore a lot of energy is required to break the strong covalent bonds.

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

3.2.1
Why are the melting points of phosphorus, sulphur, chlorine and argon low?

A

The m.p.s of phosphorus (P4), sulphur (S8), chlorine (Cl2) + argon (Ar) are low.
* P4, S8 and Cl2 are simple covalent molecules and little energy is required to overcome the weak van der Waals’ forces between the molecules.
* Ar exists as atoms and very little energy is required to overcome the weak van der Waals forces between the atoms.

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

3.2.1
Why do the melting points of elements after Si increase from phosphorus to sulfur then decrease again?
- attractions between molecules
- nuclear charge

A

The m.p.s of the elements after Si increase from phosphorus to sulfur then decrease again.
* Attractions between molecules = van der Waals’ forces (as molecules = non-polar).
* Greater the number of electrons, greater the induced dipole attractions, therefore greater van der Waals’ forces of attraction between molecules.
* This increases energy required to overcome attractions.
- P4 number of electrons < S8 no. of electrons therefore m.p. increase P4 to S8.
- S8 number of electrons > Cl2 no. of electrons and Ar has very low m.p. as monoatomic (resulting in very weak van der Waals forces) therefore m.p. decrease again.

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

3.2.1
Why does the first ionisation energy increase across a period?

A
  • Increase nuclear charge with similar shielding across the period, leading to stronger nuclear attraction.
  • Therefore atomic radius decrease across the period.
  • Therefore outer electron closer to the nucleus.
    *More energy required to remove outer electron.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

3.2.1
Why are the first ionisation energy of atoms of group 3 elements is lower than
expected?

A
  • Group 3’s outer electron is in the p sub shell whilst group 2’s outer electron is in the s sub-shell.
  • Therefore group 3’s outer electron is further from the nucleus than group 2’s + has more shielding than group 2 (due to more inner electrons).
  • Therefore weaker nuclear attraction, so electron more easily removed (less energy required to do so).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

3.2.1
Why are the first ionisation energy of atoms of group 6 elements is lower than
expected?

A
  • Group 6 atoms have a p4 arrangement the repulsion of 2 electrons in the same p orbital leads to less energy being required to remove the outer electron.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

3.2.2
What are the trends of atomic radius down Group 2?

A

Atomic radius increases down the group because…
*No. of shells increases down the group
*Therefore more shielding + therefore outer electrons further away from nucleus so…
*weaker nuclear attraction

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

3.2.2
What are the trends of first ionisation energy down Group 2?

A

First ionisation energy decreases down the group because:
*Number of shells increases down the group
*Therefore more shielding and Therefore outer electron further away from nucleus so
*weaker nuclear attraction therefore outer electron held less tightly
*Therefore easier to remove outer electron (requires less energy).

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

3.2.2
What are the trends of melting point down Group 2?

A

M.p.s decrease down the group because…
*Ions all have a +2 charge and same number of delocalised electrons per atom.
*However, size of metal ions increase down the group therefore atomic radius increase
*Therefore outer electrons further from nucleus so weaker nuclear attraction
*Therefore strength metallic bonding decrease

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

3.2.2
What are the first 4 metals in Group 2?

A
  • Magnesium (Mg)
  • Calcium (Ca)
  • Strontium (Sr)
  • Barium (Ba)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

3.2.2
What occurs when Magnesium (Mg) reacts with water?

A

Reacts very slowly with warm water - few bubbles.
* Mg(s) + 2H2O(l) → Mg(OH)2 + H2 BUT, reacts vigorously with steam.
* Mg(s) + H2O(g) → MgO + H2
- MgO is formed rather than steam as the hydroxide is not stable at higher temperatures and thermally decomposes to give MgO and H2O.

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

3.2.2
What occurs when Calcium (Ca) reacts with water?

A

Reacts with cold water and fizzing is seen in an exothermic reaction. White ppt. forms.
* Ca + 2H2O → Ca(OH)2 + H2

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

3.2.2
What occurs when Strontium (Sr) reacts with water?

A

Reacts vigorously with cold water and fizzing is seen in a highly exothermic
reaction.
* Sr + 2H2O → Sr(OH)2 + H2

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

3.2.2
What occurs when Barium (Ba) reacts with water?

A

Reacts violently with cold water and fizzing is seen in a highly exothermic reaction.
* Ba + 2H2O → Ba(OH)2 + H2

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

3.2.2
What is the trend of reactivity down Group 2?
- Why is this the trend

A

Reactivity increases down the group because
* Metals lose outer electrons when they react.
* As we go down the group number of shells in therefore more shielding.
* Therefore weaker nuclear attraction and electron held less tightly by nucleus as we go down the group.
* Hence electron is lost more easily and metal = more reactive.

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

3.2.2
How can the Relative Solubilities of Group 2 Hydroxides in Water be found?
- what must be added

A

The relative solubilities can be found by adding a solution of NaOH to solutions of the Group 2 ions + observing ppt.

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

3.2.2
What is the solubility of Magnesium hydroxide?

A

Sparingly soluble in water (as sol. is slightly alkali indicating some OH- dissolved)
= thick white ppt.
* Mg2+(aq) + 2OH-(aq) → Mg(OH)2(s)

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

3.2.2
What is the solubility of Calcium hydroxide?

A

Slightly soluble in water = white ppt.
* Ca2+(aq) + 2OH-(aq) → Ca(OH)2(s)

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

3.2.2
What is the solubility of Strontium hydroxide / Barium hydroxide?

A

Soluble in water = no ppt.

25
Q

3.2.2
What is the trend in solubility of hydroxides down Group 2?

A

The solubility of hydroxides down Group 2 increases

26
Q

3.2.2
How can the Relative Solubilities of Group 2 sulphates in Water be found?
- what must be added

A

The relative solubilities can be found by adding a solution of Na2SO4 to solutions of the Group 2 ions + observing ppt.

27
Q

3.2.2
What is the solubility of Mganesium sulfate?

A

Soluble in water = no ppt.

28
Q

3.2.2
What is the solubility of Calcium sulfate?

A

Sparingly soluble in water = thin white ppt.
* Ca2+(aq) + SO42-(aq) → CaSO4(s)

29
Q

3.2.2
What is the solubility of Stronstium sulfate?

A

Insoluble in water = white ppt.
* Sr2+(aq) + SO42-(aq) → SrSO4(s)

30
Q

3.2.2
What is the solubility of Barium sulfate?

A

Insoluble in water = thick white ppt.
* Ba2+(aq) + SO42-(aq) → BaSO4(s)

31
Q

3.2.2
What is the trend in solubility of sulphates down Group 2?

A

The solubility of sulphates down Group 2 decreases

32
Q

3.2.2
How do you test for sulfate ions?

A

1) To 1cm3 of unknown solution add 1cm3 of dilute HCl acid.
* The HCl acid removes any other ions (e.g. carbonate ions) which may affect the test by giving a white ppt. with barium chloride solution = false positive result.
2) Add 1cm3 of barium chloride solution. If sulphate ions present: white ppt formed Ba2+(aq) + SO42-(aq) → BaSO4(s)
- If no sulphate ions present: no ppt formed

33
Q

3.2.2
What are the Selected uses of the Magnesium and it’s Compounds?

A

Magnesium is used in the extraction of titanium from its ore.
* The main titanium ore, titanium(IV) oxide (TiO2) is first converted to titanium(IV) chloride (TiCl4) by heating it with carbon in a stream of chlorine gas.
* The titanium chloride is then purified by fractional distillation, before being reduced by magnesium in a furnace at almost 1000°C
- TiCl4 + 2Mg → Ti + 2MgCl2

34
Q

3.2.2
What are the Selected uses of the Magnesium hydroxide and it’s Compounds?

A

Mg(OH)2 is used in medicine as a suspension in water known as ‘milk of magnesia’ to neutralise excess acid in the stomach.

35
Q

3.2.2
What are the Selected uses of the Calcium hydroxide and it’s Compounds?

A

Ca(OH)2 is used in agriculture in solid form known as ‘slaked lime’ to neutralise acidic soil.

36
Q

3.2.2
What are the Selected uses of the Calcium oxide / Calcium carbonate and it’s Compounds?

A

CaO / CaCO3 is used to remove SO2 from flue gases (= by-products of the combustion of fossil fuels) to prevent the formation of acid rain.

37
Q

3.2.2
What are the Selected uses of the Barium sulfate and it’s Compounds?

A

BaSO4 is used in medicine as a ‘Barium meal’ given to patients to eat who need x rays of their intestines.
* The barium absorbs the X-rays and so when BaSO4 gets to the gut the outline of the gut can be located using X-rays.
* Although Barium ions are toxic it is safe to use here because barium sulphate is insoluble therefore not absorbed into the blood.

38
Q

3.2.3
What is the appearance of group 7 elements?
fluorine, chlorine, bromine and iodine

A
  • Fluorine = poisonous pale yellow gas.
  • Chlorine = poisonous green gas.
  • Bromine = toxic red-brown volatile liquid - it forms a red-brown vapour.
  • Iodine = shiny grey solid - it sublimes to form a violet vapour w/ gentle heating.
39
Q

3.2.3
What are the trends in properties down group 7?

A
  • Electronegativity decreases down the group
  • B.p.s increase down the group
  • Oxidising power decreases down the group
40
Q

3.2.3

A
  • Number of shells increase down the group therefore size of atoms increase so.
  • bonding electrons in a covalent bond are further from the nucleus + there is more shielding.
  • Therefore weaker attraction between positively charged nucleus and bonding pair of electrons.
  • Therefore element has lower electronegativity.
41
Q

3.2.3

A
  • Size of diatomic molecules increase down the group.
  • Larger molecules have more electrons, leading to greater induced dipole-dipole forces.
  • Therefore greater van der Waals’s forces between molecules.
  • Therefore more energy required to overcome the greater van der Waals’s forces as you go down the group.
42
Q

3.2.3

A

An oxidising agent accepts electrons.
* Size of ions increase down the group.
* Therefore outer electrons are more shielded and further away from the nucleus.
* Therefore electrostatic force of attraction by nucleus on the additional electron becomes weaker down the group.
* Therefore harder to gain an electron.

43
Q

3.2.3
in displacement reactions, what would we expect from our knowledge of oxidising powers of halogens decrease down the group?

A

…Fluorine to displace all other halogens from solutions of halide
compounds.
…Chlorine to displace bromide and iodide from solutions of bromide
iodide compounds.
…Bromine to displace iodide from a solution of an iodide compound.

44
Q

3.2.3
What occurs when potassium chloride solution KCl (aq) - colourless - reacts with Cl2 (aq), Br (aq), I2 (aq)?

A
  • Cl2 (aq) : no reaction
  • Br (aq) : no reaction
  • I2 (aq) : no reaction
45
Q

3.2.3
What occurs when potassium bromide solution KBr (aq) - colourless - reacts with Cl2 (aq), Br (aq), I2 (aq)?

A
  • Cl2 (aq) : orange solution (Br2) formed
  • Br (aq) : no reaction
  • I2 (aq) : no reaction
46
Q

3.2.3
What occurs when potassium iodide solution KI (aq) - colourless - reacts with Cl2 (aq), Br (aq), I2 (aq)?

A
  • Cl2 (aq) : brown solution (I2) formed
  • Br (aq) : brown solution (I2) formed
  • I2 (aq) : no reaction
47
Q

3.2.3
What does a reducing agent do?

A

A reducing agent donates electrons. They, themselves, are OXIDISED.

48
Q

3.2.3
What does a reducing power do?
- why does it increase down group 7

A

Reducing power increases down the group because:
* Size of the ions increase down the group.
* Therefore outer electrons are more shielded and further away from the
nucleus.
* Therefore electrostatic force of attraction by nucleus on outer
electrons becomes weaker down the group.
* Therefore easier to lose an electron.

49
Q

3.2.3
What occurs in reactions of solid sodium halides with concentrated sulphuric acid?
- Fluoride (F-)

A

NaF + H2SO4 → NaHSO4 + HF NOT REDOX - it is an ACID/BASE REACTION
* Observations: misty white fumes (HF) are evolved.

50
Q

3.2.3
What occurs in reactions of solid sodium halides with concentrated sulphuric acid?
- Chloride (Cl-)

A

NaCl + H2SO4 → NaHSO4 + HCl NOT REDOX - it is an ACID/BASE REACTION
* Observations: misty white fumes (HCl) are evolved.

51
Q

3.2.3
What occurs in reactions of solid sodium halides with concentrated sulphuric acid?
- Bromide (Br-)

A

NaBr + H2SO4 → NaHSO4 + HBr NOT REDOX - it is an ACID/BASE REACTION
2HBr + H2SO4 → Br2 + SO2 + 2H2O REDOX
* Observations, reaction 1:
* misty white fumes (HBr) and red-brown vapour (Br2) are evolved.
* Observations, reaction 2:
- Br is oxidised from -1 (in HBr) to 0 (in Br2) therefore bromine = oxidation product. - S is reduced from +6 (in H2SO4) to +4 (in SO2) therefore sulphur dioxide = reduction product.

52
Q

3.2.3
What occurs in reactions of solid sodium halides with concentrated sulphuric acid?
- Iodide (I-)

A

NaI + H2SO4 → NaHSO4 + HI NOT REDOX
2HI + H2SO4 → I2 + SO2 + 2H2O REDOX
6HI + H2SO4 → 3I2 + S + 4H2O REDOX
8HI + H2SO4 → 4I2 + H2S + 4H2O REDOX
* Observations (all these reactions happen in succession - not in isolation): misty white fumes evolved (HI), purple vapour evolved (I2), yellow solid formed (S), rotten egg smell (H2S) + black solid formed (I2).
* Redox:
➜ For the 1st redox reaction.
- the I is oxidised from -1 (in HI) to 0 (in I2) the S is reduced from +6 (in H2SO4) to +4 (in SO2)
➜ For the 2nd redox reaction,
- the I is oxidised from -1 (in HI) to 0 (in I2) the S is reduced from +6 (in H2SO4) to 0 (in S)
➜ For the 3rd redox reaction,
- the I is oxidised from -1 (in HI) to 0 (in I2) the S is reduced from +6 (in H2SO4) to -2 (in H2S)
Therefore oxidation product = iodine; reduction products = sulphur dioxide, sulphur and hydrogen sulphide.

53
Q

3.2.3
How do you identify halide ions with dilute nitric acid (HNO3), followed by silver(I) nitrate (AgNO3) solution?

A
  • Add dilute nitric acid (HNO3), followed by silver(I) nitrate (AgNO3) solution.
    Ag+(aq) + Cl-(aq) → AgCl(s) = white ppt. formed
    Ag+(aq) + Br-(aq) → AgBr(s) = cream ppt. formed
    Ag+(aq) + I-(aq) → AgI(s) = yellow ppt. formed
  • The dilute nitric acid removes other ions which would react with the silver nitrate solution (e.g. carbonates/sulphates/hydroxides)
    N.B. silver nitrate solution does not form ppt. with fluoride ions in solution as silver fluoride is soluble in water. So, we can’t use it as test.
54
Q

3.2.3
How do you identify halide ions with ammonia solution?

A

AgCl: will redissolve in dilute and concentrated ammonia solution to form a colourless solution.
AgBr: does not redissolve in dilute ammonia solution but does redissolve in conc. ammonia solution forming a colourless solution.
AgI does not redissolve in dilute or conc. ammonia solution.

55
Q

3.2.3
What reaction occurs when chlorine mixes with water?

A

When you mix chlorine with water, it undergoes disproportionation (This means Chlorine, Cl2 is both oxidised and reduced).
Cl2 + H2O ⇌ HClO + HCl
* The Cl is oxidised from 0 (Cl2) to +1 (HOCl)
* The Cl is reduced from 0 (Cl2) to -1 (HCl)

56
Q

3.2.3
What are the advantages + disadvantages of chlorine and chlorate?

A
  • Chlorate(I) ions kill bacteria, this is why chlorine is used in water treatment to kill bacteria. It’s been used to treat drinking water and the water in swimming pools.
  • The benefits to health (including, the irradiation of bacterial diseases like cholera) from using chlorine OUTWEIGH the fact it’s toxic / carcinogenic to humans.
    In sunlight (UV), chlorine can decompose water to form chloride ions and oxygen.
    2Cl2 + 2H2O ⇌ 4HCl + O2
57
Q

3.2.3
What occurs in the reaction of Chlorine with Cold, Dilute, Aqueous NaOH (making bleach)?
- what is observed

A

When you mix chlorine gas with cold, dilute, sodium hydroxide solution at room temperature it undergoes disproportionation.
Cl2 + 2NaOH → NaCl + NaClO + H2O
* The Cl is oxidised from 0 (Cl2) to +1 (NaClO)
* The Cl is reduced from 0 (Cl2) to -1 (NaCl)
Observation: green gas forms a colourless solution.
One of the products formed is sodium chlorate(I), NaClO. It’s in solution in this case and that is bleach (which kills bacteria)

58
Q

3.2.4

A

AQA Chemistry A level (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions