4A:Elements of Group 1 and 2 Flashcards

1
Q

Give some properties of group 1 metals

A

Less dense than water
Low melting points
Soft

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2
Q

How does ionisation energy change going down group 2 and why?

A

Decreases
Every element has an extra electron shell
More shielding occurs, distance from the nucleus increases, and effective nuclear charge doesn’t change

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3
Q

How does melting temperature change going down group 2 and why?

A

Decreases

Charge density decreases as you do down the group so less energy needed to overcome electrostatic attraction

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4
Q

How does atomic and ionic radii change going down group 1 & 2 and why?

A

Increases

Number of orbitals increases going down the group

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5
Q

What is the first ionisation energy of group 2 metals in comparison to group 1 metals?

A

Group 2 metals have larger first ionisation energy

As they have an increased nuclear charge but decreased radii

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6
Q

What is the melting points of group 2 metals in comparison to group 1 metals?

A

Higher melting points

As they lose 2 electrons per atom for metallic bonding therefore it is stronger

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7
Q

What is the electrical conductivity of group 2 metals in comparison to group 1 metals?

A

Better electrical conductivity

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8
Q

What is the hardness of group 2 metals in comparison to group 1 metals?

A

Harder than group 1 metals

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9
Q

What is the oxidation number of group 1 and 2 ions?

A

+1 : Group 1

+2 : Group 2

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10
Q

What are group 1 and 2 metals usually in redox reactions?

A

Reducing agents

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11
Q

What happens when group 2 metals react with water?

A
Metal hydroxides (aq) and hydrogen are formed
M + 2H2O -> M(OH)2 + H2
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12
Q

How does the reactivity of the group 1 and 2 metals change as you go down?

A

They get more reactive (outer electron more easily lost)

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13
Q

What happens when group 2 metals react with oxygen?

A

Burn brightly in air (except beryllium) to form white solids

2M + O2 -> 2MO

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14
Q

What happens when group 2 metals react with chlorine?

A

Solid white chlorides form (except beryllium which forms a covalent anhydrous chloride)
M + Cl2 -> MCl2

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15
Q

How reactive are group 2 metals in relation to group 1?

A

Less reactive as group 1 only need to lose 1 electron

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16
Q

Why must Mg and Ca be reacted with steam in order to form their metal oxides?

A

They are not as reactive as the other group 2 metals

In cold water they form their metal hydroxides instead

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17
Q

What are the oxides and hydroxides of group 2?

A

Bases (will react with water to form OH- ions

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18
Q

What is the exception to the group 2 oxide bases?

A

Beryllium oxide - doesn’t react with water & hydroxide is insoluble
Magnesium oxide - reacts slowly & hydroxide isn’t very soluble

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19
Q

How does the strength of the base change going down group 2?

A

Increases as they become more soluble

20
Q

As group 2 metal oxides/hydroxides are bases what can they do?

A

Neutralise dilute acids to form corresponding salts

21
Q

What is produced when calcium oxide reacts with water?

A

Reacts quickly to form Ca(OH)2

Limewater

22
Q

What does amphoteric mean?

A

A chemical which can react as both an acid or an alkali

23
Q

How does the solubility of group 2 hydroxides change going down the group?

A

Becomes more soluble

24
Q

How does the solubility of group 2 sulphates change going down the group?

A

Decreases in solubility

25
Q

What is a barium meal?

A

Used in medicine as very insoluble (barium sulphate) to highlight areas of the body

26
Q

What happens when group 2 oxides react with hydrochloric acid?

A

MO + 2HCl -> MCl2 (aq) + H2O

27
Q

What happens when group 2 hydroxides react with hydrochloric acid?

A

M(OH)2 (aq/s) + 2HCl -> MCl2 (aq) + 2H20

28
Q

What happens when group 2 hydroxides react with sulphuric acid?

A

M(OH)2 (aq/s) + H2SO4 -> MSO4 (aq/s) + 2H20

29
Q

What is thermal decomposition?

A

When a substance breaks down when heated

30
Q

What does a thermally stable compound do?

A

Requires more heat to break it down

31
Q

How can anions be made unstable?

A

By the presence of a cation

This distorts the anion

32
Q

What is the affect of the distortion of anions?

A

Greater the distortion the less stable the compound

33
Q

How does the size of the cation affect the distortion?

A

The larger the cation, the less the distortion

As lower charge density

34
Q

Why do elements in group 1 & 2 become more thermally stable going down the group?

A

Charge density decreases going down group
Causes less distortion of the anion
Therefore more stable

35
Q

What is the thermal stability of group 1 in comparison to group 2 metals?

A

Group 1 compounds are more thermally stable

As greater charge of group 2 metals cause more distortion

36
Q

What is the thermal stability of group 1 carbonates?

A
Thermally stable
(except lithium carbonate)
37
Q

What is the thermal stability of group 2 carbonates?

A

Decomposes easily

MCO3 (s) -> MO (s) + CO2

38
Q

What is the thermal stability of group 1 nitrates?

A

Decomposes easily
(Except lithium)
2MNO3 (s) -> 2MNO2 (s) + O2

39
Q

What is the thermal stability of group 2 nitrates?

A

Decompose easily

2M(NO3)2 (s) -> MO (s) + 4NO2 + O2

40
Q

How can you test the thermal stability of nitrates?

A

How long it takes to produce a certain amount of oxygen

How long until a certain amount of NO2 is produced

41
Q

How can you test the thermal stability of carbonates?

A

How long it takes for a certain amount of carbon dioxide to be produced

42
Q

How does the thermal decomposition change going down group 1 and 2?

A

Thermal stability increases going down the group

43
Q

How does the ion size change the polarizing affect?

A

Smaller cations have a greater polarizing affect

Causing it to decompose more readily

44
Q

What are the flame colours of group 1 metals?

A
Li - Red
Na - Orange/yellow
K - lilac
Rb - red
Cs - blue
45
Q

What are the flame colours of group 2 metals?

A

Ca - brick-red
Sr - crimson
Ba - green

46
Q

How would you perform a flame test?

A

Mix compound with a few drops of hydrochloric acid
Heat a piece of platinum in a bunsen flame to clean it
Dip wire into mixture and hold it in the flame