1.6 Flashcards
1
Q
Oxidation is
A
Loss of electrons
2
Q
Reduction is
A
Gain of electrons
3
Q
All elements have an oxidation number of
A
0
4
Q
Hydrogen’s oxidation number in compounds is usually
A
+1
5
Q
Oxygen’s oxidation number in compounds is usually
A
-2
6
Q
Group 1 and 2 elements’ oxidation number are
A
+1 and +2
7
Q
Oxidation number of the elements in a compound must add up to
A
0
8
Q
Oxidation number of the elements in an ion must add up to
A
The charge
9
Q
S-block and oxygen/ air
A
Solid white Oxides
10
Q
Group 2 and acid
A
Salt
11
Q
Trend in reactivity of s block elements down the group
A
Increases
All react vigorously with acids
React with oxygen and burn in air
Caesium inflames spontaneously
12
Q
Is G1 or G2 more reactive
A
G1- easier to lose 1 electron than 2
13
Q
All oxides and hydroxides of s block elements are
A
Basic
14
Q
All salts of which group are soluble
A
Group 1
15
Q
Describe trend in solubility of group 2 hydroxides
A
Increases down the grouo
16
Q
Describe the trend in group 2 sulphates
A
Decreases down the group
17
Q
Solubility of group 2 carbonates
A
Insoluble
18
Q
Solubility of group 2 nitrates
A
Soluble
19
Q
Flame colour of Li
A
Red
20
Q
Flame colour of sodium
A
Yellow/orange
21
Q
Flame colour of potassium
A
Lilac
22
Q
Flame colour of calcium
A
Brick red
23
Q
Flame colour of strontium
A
Crimson res
24
Q
Flame colour of barium
A
Apple green
25
Flame colour of magnesium
Bright white
26
Trend in thermal stability of Group 2 hydroxides and carbonates
Increases down the group
27
Colour of all s-block salts
White
28
What is volatility
How readily a substance vapourises
29
Trend in volatility of halogens
Decreases down the group - stringer intermolecular forces
30
Halogens at room temperature
Cl - green has
Br - red/brown liquid
I - grey solid
31
Trend in reactivity of halogens
Decreases down the group
| Harder to attract electrons as theres more shielding and further from the nucleus
32
Trend in oxidising power of halogens
Decreases down the group
| Harder to attract electrons as more shielding and further from nucleus
33
Iron wool burning in halogens vapour
```
Chlorine and bromine - iron(III) halide
2Fe + 3X2 ---> 2FeBr3
Iodine - iron (II) iodide
Fe + I2 ---> FeI2
Less reactive and a weaker oxidising agent
```
34
What is the test for halogens
Silver nitrate test
35
Describe the silver nitrate test
* add few drops of nitric acid to ensure all other anions removed
* silver nitrate is added to create an insoluble silver halide
* to distinguish further aqueous ammonia is added to the precipitate
36
Results if adding silver nitrate to halides
Cl- White precipitate
Br- Cream precipitate
I- Pale yellow precipitate
37
Results of adding aqueous ammonia to insoluble silver halide
AgCl Dissolves in dilute ammonia
AgBr Dissolves in concentrated ammonia
AgI Insoluble in concentrated ammonia
38
Why is there a decreasing oxidising power down group 7
Increasing atomic radius
| Increased shielding
39
On strong heating, magnesium reacts with steam to give magnesium oxide and hydrogen.
Explain why magnesium hydroxide is not produced at this temperature
Magnesium hydroxide thermally decomposes at this temperature to form the oxide
40
Explain why the elements in group 7 become less volatile down the group
The molecular size increases down the group
There are stronger VDW forces
These require more energy to break
41
Give one test, and the expected results, which could be used to show the presence of calcium ions in the solution calcium nitrate
Flame test - brick red
42
Give a description of the flame test
Wet a splint in a HCl solution then dio it in the powder before putting it above a bunsen burner
43
Would you expect strontium sulphate to be soluble in water - why?
No as sulphates become less soluble down group 2
44
State and explain how the reactivity of the elements in group 7 varies down the group
Decreases
They react by gaining 1 electron
But as there is extra shielding and increases atomic radius it makes it harder to do so
45
State the reagents and observations for the test to show the presence of the sulphate ions in a solution
Barium chloride
| White precipitate
46
Describe what is seen when aqueous iodide ions are added to a solution which contains aqueous chlorine. Give an explanation for your observation.
Red/brown solution
| I- oxidised by Cl to brown iodine
47
State, giving a reason, whether chlorine, Cl, is a stronger or weaker
oxidising agent than bromine, Br
Stronger
| Due to having a stronger electronegativity value so the oxidising power decreases down the group
48
Write a balanced equation for the reaction of calcium with water
Ca + 2H2O ---> Ca(OH)2 + H2
49
Describe the trend in melting and boiling temperature across a period
* general increase from first to fourth element - metallic bonding
* large decrease to the fifth - giant covalent
* small general decrease to the eighth element - simple molecular covalent
50
What is an oxidising agent
Species that accepts electrons
| Becomes reduced itself
51
What is a reducinh agent
Species that donates electrons
| Becomes oxidised itself
52
Group 1 and water
* hydroxide and hydrogen formes
* react vigorously with cold water
* becomes more vigour as you go down the group
53
What can be seen when Lithium reacts with cold water
It floats, fizzes and moves
54
What can be seen when sodium react with cold water
Floats, fizzes, moves and melts
55
What can be seen when potassium reacts with cold water
Floats, fizzes, moves, melts and burns
56
Group 1 or 2 react less vigorously with water
Group 2
57
Magnesium with cold water
Slow
58
Calcium and cold water
Steady stream of bubbles and a white precipitate of calcium hydroxide forma
59
Group 2 and cold water
The Hydroxide and hydrogen
60
Why does the reactivity fo group 2 elements increase down the group
Ionisation energies decreases down the group so energy needed to form carions decreases
61
Why are group 1 metals more reactive than group 2 metals
Only need to lose one electron compared to losing two
62
Which kind of s block elements react with water to form a soluble hydroxide or alkali
Group 1 oxides and barium oxide
63
S block metal oxides
Strong bases
64
S block hydroxides
Alkalis as they're soluble
65
Group 1 solubility
Soluble
66
Trend in group 2 sulfates solubility
Less soluble down the group
67
Product of group 2 hydroxides decomposing on heating
The oxide and steam
68
Product of group 2 carbonates on heating
The oxide and carbon dioxide
69
Test for trend of group 2 carbonates
Heating them and seeing how long it takes for the carbon dioxide formed to turn limewater cloudy
70
Trend in melting and boiling temperatures of halogens and why
Increases down the group
| Increase in electrons, increase in induced dipole - induced dipole forces
71
Insoluble salt formation
* precipitation reaction
* two suitable solutions are mixed to form a soluble salt and an insoluble salt
* precipitate is filtered, washed and dried
72
Soluble salt formation
* usually can neutralise an acid
* excess solid is filtered
* solution is evaporated and left to cool to form crystals
