Group 7 Flashcards

1
Q

Describe the trend in atomic radius as you go down group 7

A

Increases There are more shells

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2
Q

Describe how the ionic radius compared to the atomic radius in group 7

A

The halide ion (X-) has the same number of protons as the halogen atom (X) but more electrons so the attraction is weaker.

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3
Q

Describe the trend in boiling point as you go down group 7

A

Increases The molecules are larger and have more electrons. This makes the Van Der Waals forces between the molecules are stronger and more energy is needed to overcome them.

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4
Q

Describe the trend in volatility down group 7

A

Less volatile The molecules are larger and have more electrons. This makes the Van Der Waals forces between the molecules are stronger and more energy is needed to overcome them.

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5
Q

Describe the trend in electronegativity as you go down group 7

A

Decreases Shielding increases and so the attraction is weaker therefore the nuclear attraction to the shared pair of electrons is weaker

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6
Q

Describe the trend in first ionisation energy down group 7

A

Decreases Shielding increases as there are more shells therefore the nuclear attraction to the outer electron is less and less energy is needed to remove it

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7
Q

What is the colour of, state at room temperature of, colour of the aqueous solution of and the colour in cyclohexane of Cl2.

A

Colour: green State at room temp: gas Colour of aqueous sol: pale green Colour in cyclohexane: pale green

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8
Q

What is the colour of, state at room temperature of, colour of the aqueous solution of and the colour in cyclohexane of Br2.

A

Colour: Red-brown State at room temp: liquid Colour of aqueous sol: orange Colour in cyclohexane: orange

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9
Q

What is the colour of, state at room temperature of, colour of the aqueous solution of and the colour in cyclohexane of I2

A

Colour: black State at room temp: solid Colour of aqueous sol: brown Colour in cyclohexane: purple

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10
Q

Why are the halogens more soluble in non-polar solvents?

A

They are non-polar

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11
Q

Describe the trend in solubility in water as you go down group 7

A

Decreases The halogen becomes larger

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12
Q

What are the results of the experiment that provides evidence for the trend in oxidising powers of the halogens?

A
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13
Q

What is the full equation, ionic equaion and half equations for the equation between chlorine and potassium bromide.

A
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14
Q

What is the full equation, ionic equaion and half equations for the equation between bromine and potassium iodide.

A
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15
Q

What is the full equation, ionic equaion and half equations for the equation between chlorine and potassium iodide.

A
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16
Q

Are halogens oxidising agents or reducing agents? Why?

A

Oxidising agents

They gain electrons to fro halide ions

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17
Q

What is the general equation for the oxidation of a halogen?

A
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18
Q

Describe the trend in the ability of the halogens to act as oxidising agents down group 7

A

Decreases

More shielding due to an increase in the number of shells

Therefore the ability to gain electrons is less as the nuclear attraction decreases.

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19
Q

Are halides oxidising or reducing agents?

A

Reducing

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20
Q

What are the possible reduction products of H2SO4 when it is reduced by a halide? Give the oxidation numbers and the appearence/test of the product.

A
  • Sulfuric (VI) acid, +6
  • Sulfur dioxide, +4, Turns orange dichromate paper green + choking smell
  • Sulfur, 0, yellow solid
  • H2S, -2, Turns leadethanoate paper black + smells of bad eggs
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21
Q

What is the general equation for the oxidation of a halide ion?

A
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22
Q

Describe the method of using halide ions to reduce H2SO4

A
  • Put 0.1g of the solid halide compound in a test tube
  • Add 10 drops of concentrated H2SO4
  • Warm is necessary
  • Identify as many products as you can
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23
Q

What are the observations when you react NaCl with C. H2SO4?

A

Initial: White fumes (HCl)

Subsequent: No further changes

24
Q

What are the observations when you react NaBr with C. H2SO4?

A

Initial: White fumes (HBr)

Subsequent: Brown fumes (Br2), SO2 detected

25
Q

What are the observations when you react NaI with C. H2SO4?

A

Initial: White fumes (HI)

Subsequent: Purple fumes (I2), SO2, S + H2S all detected

26
Q

What is the equation for the reaction between sodium chloride and H2SO4? Is this a redox reaction?

A
27
Q

What is the initial reaction for the reaction between sodium bromide and H2SO4? Is it a redox reaction?

A
28
Q

What are the half equations for the reaction between sodium bromide and H2SO4? Hence find the overall redox equation.

A
29
Q

What is the overall equation for the reaction between Sodium bromide and H2SO4? How is it worked out?

A

Combine the overall redox equation with the equation for the initial reaction.

30
Q

What is the initial reaction for the reaction between sodium iodide and H2SO4? Is it a redox reaction?

A
31
Q

What are the half equations for the reaction between sodium iodide and H2SO4? Hence find the overall redox equations.

A
32
Q

What are the overall redox equations for the reaction between sodium bromide and H2SO4?

A
33
Q

What are the three overall equations for the reaction between sodium iodide and H2SO4?

A
34
Q

Describe the trend of the reducing strength of the halides as you go down group 7

A

Increases

Shielding increases as there are more shells

This meand the nuclear attraction to the outer electrons is less and they are more easily donated

35
Q

Which is the strongest oxidising agent from group 7?

A

F2

36
Q

Which is the strongrst reducing agent from group 7?

A

I(-)

37
Q

Describe the test that tests for halide ions.

A
  • Make a solution of the substance to be tested
  • Add dilute nitric acid to remove other ions that interfere with the results by giving ppts (carbonates)
  • Add silver nitrate solution
  • Observe the colour of the ppt
38
Q

Why can carbonates interfere when testing for halides and halogens?

A

They give ppts

39
Q

What are the results when you mix the halide ions with silver nitrate solution? Give the colour and the name of the ppt.

A

Cl-: White, Silver chloride (AgCl)

Br-: Cream, Silver Bromide (AgBr)

I-: Yellow, Silver Iodide (AgI)

40
Q

Why do flouride ions not form a ppt with silver nitrate solution?

A

AgF is soluble in water

41
Q

What is the overall and ionic equation for the reaction between silver nitrate and sodium chloride?

A
42
Q

What is the overall and ionic equation for the reaction between silver nitrate and sodium bromide?

A
43
Q

What is the overall and ionic equation for the reaction between silver nitrate and sodium iodide?

A
44
Q

What is the general ionic equation for the reaction between silver nitrate and a sodium halide?

A
45
Q

How do you test for the trend in solubility of the silver halides?

A
  • To each ppt add dilute ammonia solution and see if the ppt dissolves
  • If not, add concentrated ammonia solution and see if it dissolves.
46
Q

How soluble is silver chloride, silver bromide and sliver iodide in ammonia?

A

Silver chloride - Soluble in dilute NH3

Silver bromide - Soluble in concentrated NH3

Silver iodide - Insoluble in dilute or concentrated

47
Q

Describe the trend in solubility of the silver halides in ammonia down group 7.

A

Becomes less soluble (starting from chlorine)

48
Q

What is the equation for the reaction between chlorine and water? What are the half equations for chlorine?

A
49
Q

What can you observe with Cl2, HCl and HClO?

A

Cl2: pale green

HCl: blue litmus paper turns red

Chloric (I) acid: litmus paper is bleached

50
Q

What doe chloric (I) acid decompose to give?

A
51
Q

What accelerates the reaction of HClO to form HCl and O2?

A

Sunlight

Platinum/metallic oxides

52
Q

What is the equation for the reaction between Cl2 and H2O in the prescence of sunlight?

A
53
Q

What are the benefits and risks of using chlorine in water treatment?

A

Benefits: Kills bacteria and so reduces the risk of water borne diseases

Risks: Cl2 is toxic in large quantities.

54
Q

What is the reaction between chlorine and dilute sodium hydroxide solution? What is the main use of the solution this forms?

A

Bleach

55
Q
A