Inorganic Chemistry and the Periodic Table Flashcards

1
Q

Trends in atomic radius for group 2 elements

A

Group 2 elements form 2+ ions when they react

Atomic radius increases down the Group.

As one goes down the group, the atoms have more shells of electrons making the atom bigger.

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2
Q

What is a common name given to group 2 metals?

A

Alkaline earth metals

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3
Q

What is the most reactive metal of group 2?

A

Barium

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4
Q

List 3 physical properties of group 2 metals

A

● High melting and boiling points
● Low density metals
● Form colourless (white) compounds

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5
Q

The highest energy electrons of group 2 metals are in which subshell?

A

S subshell

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6
Q

Does reactivity increase or decrease down group 2? Why?

A

● Increases

● Electrons are lost more easily because larger atomic radius and more shielding.

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7
Q

What happens to the first ionisation energy as you go down group 2? Why?

A

1st ionisation energy decreases as we go down group 2

Extra shells added as we go down group 2

The outer electrons are further away from the nucleus
which weakens the attraction

There is more shielding, hence the attraction between the outermost electron and the nucleus decreases

This makes it easier to remove the outer electron, so less energy is required to remove it

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8
Q

What type of reaction is the reaction between group 2 elements and oxygen?

A

Redox reaction

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9
Q

Write an equation for the reaction of calcium and oxygen

A

2Ca (s) + O2 (g) → 2CaO (s)

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10
Q

What is the product when group 2 elements react with water?

A

Hydroxide and hydrogen gas

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11
Q

Which group 2 element doesn’t react with water?

A

Beryllium

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12
Q

Which group 2 element reacts very slowly with water?

A

Magnesium

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13
Q

What type of reaction is the reaction between group 2 metal and water?

A

Redox reaction

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14
Q

Write an equation for the reaction of Barium and water

A

Ba (s) + 2H2O (l) → Ba(OH)₂ (aq) + H₂ (g)

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15
Q

What is oxidised and what is reduced in a reaction between group 2 metal and water?

A

Metal → oxidised

One hydrogen atom from each water → reduced

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16
Q

What are the products when group 2 oxide reacts with dilute acid?

A

Salt and water

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17
Q

Write an equation for the reaction of calcium and hydrochloric acid

A

CaO (s) + 2HCl (aq) → CaCl2(s) + H₂O (l)

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18
Q

What is formed when group 2 oxides react with water?

A

Metal hydroxide

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19
Q

Write an equation for the reaction between a group 2 oxide and water

A

MO (s) + H2O (l) → M(OH)2 (aq)

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20
Q

Which group 2 metal oxide is insoluble in water?

A

Beryllium oxide

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21
Q

Write an equation for the reaction between Mg(OH)2 and nitric acid

A

2HNO3 (aq) + Mg(OH)2 (aq) Mg(NO3)2 (aq) + 2H2O (l)

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22
Q

What is the trend in hydroxide solubility down group 2?

A

Increases down the group

Mg(OH)₂ is slightly soluble

Ba(OH)₂ creates a strong alkaline solution

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23
Q

What is the trend in sulphate solubility down group 2?

A

Group 2 sulphates become less soluble down the group with BaSO4 being the least soluble.

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24
Q

Explain the reasons for the trend of thermal stability in group 1 and 2 carbonates

A

Group 2 carbonates are more thermally stable as you go down the group. This is because the cations get bigger so therefore have less of a polarising effect distorting the carbonate ion less. As C-O bond is not weakened as much it harder to break down

Group 1 carbonates do not decompose except for lithium. This is because they don’t have a big enough charge density to polarise the carbonate ion as they only form 1+ ions. However Lithium ion is small enough to have a polarising effect so therefore lithium carbonate can decompose.

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25
Q

Explain the reasons for the trend of thermal stability in group 1 and 2 nitrates

A

The ease of thermal decomposition decreases down group 2 and this is because down the group the ions get larger and therefore has less charge density = less polarisation of nitrate anion and less weakening of the N―O bond.

Group 1 nitrate do not decompose with the exception of Lithium nitrate. Lithium ion is smaller enough to charge polarisation of the nitrate anion and thus weakening the N-O bond.

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26
Q

Flame test colours group 2

A

Magnesium: no flame colour (the energy emitted is outside visible spectrum)
Calcium: brick red
Strontium: red
Barium: pale green

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27
Q

How do you carry out a flame test?

A
  1. Use a nichrome wire
  2. Sterilise the wire by dipping in concentrated hydrochloric acid and then heating in Bunsen flame
  3. Make sure the sample powdered or grinded
  4. Dip wire in solid and put in Bunsen flame and observe flame
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28
Q

How are the colours from the flame test formed?

A

The heat causes the electron to get excited and thus move to a higher energy level but at this higher level the electron is unstable so then moves back down.

As it moves from a higher to lower energy level energy is emitted in the form of visible light energy which is the colour you see.

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29
Q

What group elements are referred to as halogens?

A

Group 7

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30
Q

List 2 properties of halogens

A

● Low melting and boiling points

● Exist as diatomic molecules

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31
Q

What is the trend in boiling point down group 7? Why?

A

Increases down the group because: -size of atom increases as more occupied electron shells → stronger London forces of attraction between molecules, take more energy to break

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32
Q

What is the trend in reactivity down group 7? Why?

A

Reactivity decreases because:
● Atomic radius increases
● Electron shielding increases
● Ability to gain an electron and form 1- ions decreases

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33
Q

Explain the trend of electronegativity down group 7

A

Down the group the electronegativity of the elements decreases.
This is because the atomic radii increases due to the increasing number of shells so there is reduced nuclear attraction between the outermost electron and the nucleus.

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34
Q

What is the trend in oxidising ability down the group? Why?

A

Decreases down group (Cl strongest, I weakest)

This is because Cl has the fewest occupied electron shells, greatest force of attraction between outer electrons and nucleus and thus is the easiest to gain electrons and be reduced → best oxidising agent

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35
Q

What is the trend in reducing ability of the halides down the group? Why?

A

Increases down the group (Cl- weakest, I- strongest)

This is because I- has the most occupied electron shell so outer electrons are further from the nucleus, weakest force of attraction between outer electrons and positive charge of nucleus and thus is the easiest to be oxidised and lose electrons → best reducing agent

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36
Q

When a more reactive halogen displaces a less reactive halide, what is the reaction called?

A

Displacement reaction

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37
Q

What is the colour of chlorine in water?

A

Pale green

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38
Q

What is the colour of bromine in water?

A

Orange

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39
Q

What is the colour of iodine in water?

A

Brown

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40
Q

What is the colour of chlorine in cyclohexane?

A

Pale green

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41
Q

What is the colour of bromine in cyclohexane?

A

Orange

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42
Q

What is the colour of iodine in cyclohexane?

A

Violet

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43
Q

Out of the 3 halides Cl-, Br- & I-, which one of these can be oxidised by chlorine?

A

Br- & I- ions

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44
Q

Write the equation for chlorine oxidising bromide ions

A

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

Yellow solution

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45
Q

Write the equation for Cl2 oxidising 2I- in cyclohexane and associated colour change

A

Cl₂ (aq) + 2I- (aq) → 2Cl- (aq) + I₂ (aq)

Purple solution

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46
Q

Out of the 3 halides Cl- , Br- & I- , which one of these can be oxidised by bromine?

A

I- ions

47
Q

Write the equation for bromine oxidising iodide ions

A

Br₂ (aq) + 2I- (aq) → 2Br- (aq) + I₂ (aq)

Brown solution

48
Q

Out of the 3 halides Cl- , Br- & I- , which one of these can be oxidised by iodine?

A

Does not oxidise Cl- or Br-

49
Q

Define disproportionation

A

The oxidation and reduction of the same element in a redox reaction

50
Q

What is the equation for the reaction of Cl2 with water?

A

Cl₂ (g) + H₂O (l) → HClO (aq) + HCl (aq)

51
Q

What type of reaction is the reaction of chlorine with water?

A

Disproportionation; chlorine is both oxidised and reduced

52
Q

Why is chlorine added to drinking water?

A

It kills the bacteria in the water and makes it safer to drink

53
Q

What are the two forms of the chlorate ion?

A

ClO- is chlorate (I)

ClO₃- is chlorate (V)

54
Q

What is the equation for forming bleach?

A

Cold dilute alkali
Cl₂ (aq) + 2NaOH (aq) → NaCl (aq) + NaClO (aq) + H₂O (l)
NaClO is bleach

55
Q

Show that the reaction of chlorine with hot dilute NaOH is a disproportionation reaction

A

3Cl2 (aq) + 6 NaOH(aq) 5 NaCl (aq) + NaClO3 (aq) + 3H2O (l)
Chlorine is been reduced and oxidised.

Oxidation state of chlorine has gone from:
0 to -1 in NaCl = reduction

0 to +1 in NaClO3 = oxidation

56
Q

What do you use to test for halide ions?

A

Acidified Silver nitrate

AgNO3

57
Q

Why do you add HNO3? Why not HCl?

A

To remove CO₃2

Adding HCl would add Cl- ions, giving a false positive result

58
Q

Result and equation for Chloride (cl-) test?

A

white ppt

Ag+ + Cl- → AgCl (s)

59
Q

What is the result and equation for the test for Bromide ions (Br-)?

A

Cream ppt

Ag+ + Br- → AgBr (s)

60
Q

What is the result and equation for the test for Iodide ions (I-)?

A

Yellow ppt

Ag+ + I- → AgI (s)

61
Q

What happens (+ equations) to each of the silver halide precipitates when dilute/conc ammonia are added?

Silver chloride

A
Silver chloride (AgCl-) dissolves in both dilute and conc ammonia
AgCl (s) + 2NH₃ (aq) → [Ag(NH₃)₂]+ (aq) + Cl
62
Q

What happens (+ equations) to each of the silver halide precipitates when dilute/conc ammonia are added?

Silver bromide

A

Silver bromide (AgBr)- only dissolves in conc ammonia

AgBr (s) + 2NH₃ (aq) → [Ag(NH₃)₂]+ (aq) + Br

63
Q

What happens (+ equations) to each of the silver halide precipitates when dilute/conc ammonia are added?

Silver iodide

A

Silver iodide (AgI-) will not dissolve in either concentrated or dilute ammonia

64
Q

What products are formed when I- reduces H2SO4?

A

Do equations for all 4. H₂SO₄ + 2I- → SO₄2- + 2HI H₂SO₄ + 2H+ + 2I- → SO₂ + I₂ + 2H₂O (SO2 is a choking gas with a pungent odour) H₂SO₄ + 6H+ + 6I- → S + 3I₂ + 4H₂O (S is a yellow solid) H₂SO₄ + 8H+ + 8I- → H₂S + 4I₂ + 4H₂O (H2S smells of bad/rotten eggs)

65
Q

What are halogens?

A

Halogens are oxidising agents

CL2 + 2e- → 2cl

66
Q

What are halides?

A

Halides are reducing agents

2Cl → Cl2 + 2e-

67
Q

The smaller the halogen

A

the stronger the oxidising power

68
Q

The larger the halide

A

the stronger the reducing power

69
Q

Reduction of sulphur

A

Whenever sulphur is reduced, it can produce sulphur dioxide, which is further reduced to hydrogen sulphide and then reduced to sulphur

70
Q

What products are formed when iodide ions reduces Sulfuric acid?

A

H₂SO₄ + 2I- → SO₄2- + 2HI

71
Q

What products are formed when iodide ions reduces Sulfuric acid to sulfur dioxide?

A

H₂SO₄ + 2H+ + 2I- → SO₂ + I₂ + 2H₂O (SO2 is a choking gas with a pungent odour)

72
Q

What products are formed when iodide ions reduces Sulfur dioxide to sulfur?

A

H₂SO₄ + 6H+ + 6I- → S + 3I₂ + 4H₂O (S is a yellow solid)

73
Q

What products are formed when iodide ions reduces Sulfuric acid to hydrogen sulphide?

A

H₂SO₄ + 8H+ + 8I- → H₂S + 4I₂ + 4H₂O (H2S smells of bad/rotten eggs)

74
Q

What are the products of Br- + H2SO4?

A

HBr and SO₂

75
Q

Does Cl- reduce H2SO4?

A

No, not a powerful enough reducing agent; only HCl is formed

76
Q

How can you test for carbonate ions, CO32-?

A

Add strong acid to the sample
Collect the gas produced
Pass through lime water

77
Q

What are the observations for a positive test of carbonate ions, CO32-?

A

Fizzing Limewater turns cloudy

78
Q

Write an equation for the carbonate ion test

A

CO32- (aq) + 2H+ (aq) → H2O (aq) + CO2 (g)

79
Q

How can you test for sulphate ions, SO42-?

A

● Add dilute hydrochloric acid and barium sulphate to the sample

80
Q

What are the observations for a positive test of sulfate ions, SO42-?

A

White precipitate of barium sulfate is produced

81
Q

Write an equation for the sulfate ion test

A

Ba2+ (aq) + SO42- (aq) → BaSO4 (s)

82
Q

When testing for carbonate, sulfate and halide ions, in which order should the tests be carried out and why?

A
  1. Carbonate test
  2. Sulfate test
  3. Halide test

Because barium ions forms insoluble precipitate of BaCO3 and silver ions form insoluble precipitate of Ag2SO4

83
Q

How can you test for ammonium ions, NH4+?

A

Add sodium hydroxide to the sample and warm it

Test the gas produced with red litmus paper

84
Q

What are the observations for positive ammonium ions test?

A

● Red litmus paper turns blue ● Ammonia has a pungent smell

85
Q

Write the equation for ammonium ions test

A

NH4+ (aq) + OH- (aq) → NH3 (aq) + H2O (aq)

86
Q

Reactions of group 2 elements with oxygen

A

Group 2 elements react with oxygen to produce metal oxides

Group 2 oxides produce white solids

Reactions become more vigorous as you go down the group

87
Q

General equations for the reactions of group 2 elements with oxygen

A

2X(s) + O2(g) → 2XO(s)

The products are oxides containing X^2+ and O^2- ions

88
Q

Reactions of group 2 elements with chlorine

A

The group 2 elements react with chlorine when heated in the gas

Group 2 elements react with chlorine to produce metal chlorides

Reactions become more vigorous as you go down the group

89
Q

General equations for the reactions of group 2 elements with chlorine

A

X (s) + Cl2(g) → XCl2 (s)

The products are chlorides containing X^2+ and Cl- ions

90
Q

Reactions of group 2 elements with water

A

Group 2 elements react with water to produce metal hydroxides

The reaction between magnesium and water is very slow and does not proceed completely.

Calcium, strontium and barium react with increasing vigour (i.e. down the group), which can be seen by the increase in effervescence

91
Q

Observations when group 2 elements react with water

A

One would observe:

  • Fizzing, (more vigorous down group)
  • The metal dissolving, (faster down group) 
  • The solution heating up (more down group)
  • With calcium a white precipitate appearing (less precipitate forms down group)
92
Q

General equations for the reactions of group 2 elements with water

A

X (s) + 2H2O (l) → X(OH)2 (aq) +H2 (g)

The products are hydrogen gas and hydroxides containing X2+ and OH- ions

93
Q

How is the reaction of calcium with water different?

A

Ca (s) + 2H20 (l) → Ca(OH)2 (S) + H2 (g)

Calcium hydroxide is only slightly soluble in water, so the liquid in this experiment goes cloudy as a precipitate of calcium hydroxide forms

94
Q

Reaction of magnesium and steam

A

Magnesium reacts differently when heated in steam - it rapidly produces magnesium OXIDE and hydrogen gas in vigorous reaction.

The Mg would burn with a bright white flame.

Mg (s) + H2O (g) → MgO(s) + H2(g)

95
Q

Reactions of group 2 oxides with water

A

The group 2 oxides are classed as basic oxides, which means that they can react with water to form alkalis.

These reactions occur when the oxides are added to water

The solids react to form colourless solutions

They become more strongly alkaline as you go down the group as the hydroxides become more soluble

96
Q

General equation for the reactions of group 2 oxides with water

A

XO (s) + H20 → X(OH)2 (aq)

97
Q

Reactions of the group 2 oxides and hydroxides with acids

A

All of the group 2 oxides and hydroxides react with acids to form salts and water

These reactions can be described as neutralisation reactions

During the reactions, a white solid reacts to form a colourless solution

The reactions are exothermic

98
Q

Solubility of group 2 sulfates

A

The solubility of group 2 sulfates decreases down the group

Magnesium sulfate is classed as soluble
Calcium sulfate is slightly soluble
Strontium sulfate and barium sulfate are insoluble

99
Q

Solubility of group 2 Hydroxides

A

The solubility of group 2 hydroxides increases down the group

100
Q

The effect of heat on the Group 2 carbonates

A

All the carbonates in this Group undergo thermal decomposition to give the metal oxide and carbon dioxide gas.

All of these carbonates are white solids, and the oxides that are produced are also white solids.

As you go down the Group, the carbonates have to be heated more strongly before they will decompose.

The carbonates become more stable to heat as you go down the Group.

101
Q

Why do group 2 carbonates/nitrates become more stable as you go down the group?

A

Group 2 carbonates 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

102
Q

The effect of heat on the Group 2 nitrates

A

All the nitrates in this Group undergo thermal decomposition to give the metal oxide, nitrogen dioxide and oxygen.

The nitrates are white solids, and the oxides produced are also white solids. Brown nitrogen dioxide gas is given off together with oxygen.

Magnesium and calcium nitrates normally have water of crystallisation, and the solid may dissolve in its own water of crystallisation to make a colourless solution before it starts to decompose.

As you go down the Group, the nitrates also have to be heated more strongly before they will decompose.

The nitrates also become more stable to heat as you go down the Group.

103
Q

Effect of heat on group 1 nitrates

A

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.

104
Q

How do we test the stability of nitrates?

A

Measure how long it takes for a specific amount of oxygen to be produced using a gas syringe

Or, length of time it takes until a specific amount of NO2 is produced. NO2 is a brown gas that can easily be observed, but is toxic so must be done in a fume cupboard

105
Q

How do we test the stability 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.

106
Q

Trends in boiling points of group 7 elements

A

This increases as we go down the group

This is because the strength of the London forces increase due to the increasing size and relative mass of the atoms, so more energy is needed to break the bonds

The physical state goes from gas at the top of group 7 to solid at the bottom

107
Q

Fluorine F2

A

Pale yellow gas

108
Q

Chlorine Cl2

A

pale green gas

109
Q

Bromine Br2

A

Brown orange liquid

110
Q

Iodine I2

A

Grey solid

111
Q

Trends in electronegativity of group 7 elements

A

This decreases as we go down the group

As the halogen atoms get bigger, any bonding pair gets further and further away from the halogen nucleus, and so is less strongly attracted towards it.

In other words, as you go down the Group, the elements become less electronegative.

112
Q

Trends in melting points of group 7 elements

A

This increases as we go down the group

This is because the strength of the London forces increase due to the increasing size and relative mass of the atoms, so more energy is needed to break the bonds

113
Q

Trends in reactivity of group 7 elements

A

As you go down group 7, the halogens become less reactive.

This is because:

  • Atomic radius increases
  • Nuclear charge increases, so the nuclear attraction on the outer electrons are stronger.
  • Electron Shielding increases and outweighs the nuclear attraction.