Chapter 9 (Group 2) Flashcards

1
Q

What are group 2 elements also known as and why?

A

Alkaline earth metals because their oxides and hydroxides are alkaline.

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

How many electrons do they have in their outer shell?

A

2

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

Which orbital are the outer electrons in?

A

s-orbital

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

How does the radius of the atom change going down the group and why?

A

The atoms gets bigger as the atomic radius increases as there is an extra outer shell.

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

How does the melting point change going down the group?

A

The melting point decreases as the delocalised ‘ sea’ of electrons is further away from the positive nucleus. This means that the strength of the metallic bond decreases and the electrostatic attractive forces between positive ions and delocalised electrons weaken.

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

How does the ionisation energy change going down the group?

A

The ionisation energy decreases going down the group as the outer shell of the element become further away from the positive nucleus and the nucleus is shielded by more inner shells of electrons.

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

Why are all reactions for group 2 oxidation?

A

The elements lose both the electrons in their outer shell and go from oxidation state of 0 to oxidation state of 2+.

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

How does the reactivity with water change going down the group and why?

A

The elements become more reactive going down the group as there is more shielding between the positive nucleus and negative electrons in the outer shell so there is weaker attraction.

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

How do hydroxides appear?

A

They are white solids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does the solubility of hydroxides change down the group?

A

They become more soluble down the group.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the use of barium sulphate?

A

As barium sulphate is insoluble, it can be ingested to show digestive organs on x-rays.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is calcium hydroxide also known as and what is its use?

A

It is limewater and can be used to test for carbon dioxide and to get the correct pH for growing crops.

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

What is produced when a group 2 metal is reacted with STEAM?

A

Metal OXIDE and hydrogen

e.g. Mg (s) + H2O (g) > MgO (s) + H2 (g)

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

What is produced when a group 2 metal is reacted with WATER?

A

Metal HYDROXIDE and hydrogen

e.g. Mg + 2 H2O > Mg(OH)2 + H2

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

Which group 2 metal reacts with warm water?

A

Magnesium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which group 2 metals react with cold water?

A

Calcium, strontium, barium

17
Q

What are the observations from adding a group 2 metal to water?

A
  • 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 with other metals)
18
Q

What is the use for barium chloride?

A

Used to test for sulphate ions - white precipitate forms if sulphate is present.

19
Q

Describe the process of using magnesium to extract titanium

A

1) TiO2 (s) is converted to TiCl4 (l) at 900 degrees c.
2) The TiCl4 is purified by fractional distillation in an argon atmosphere.
3) The Ti is extorted by Mg in an argon atmosphere at 500 degrees C.

20
Q

Why is TiO2 converted to TiCl4?

A

Can be purified by fractional distillation as TiCl4 is molecular and solid at room temperature while TiO2 is ionic and solid at room temperature.

21
Q

Why can titanium not be extracted by carbon or electrolysis?

A

Forms carbonise (TiC)

Cannot be extracted baby electrolysis as it has to be very pure.

22
Q

Why is titanium expensive?

A
  • Expensive cost of magnesium
  • Batch process so is slower and requires more labour and energy is lost when the reactor cools down after stopping.
  • Use of argon and need to remove moisture (TiCl4 is susceptible to hydrolysis)
  • High temperatures required in both steps.
23
Q

List hydroxides from most to least soluble

A

Barium Hydroxide - easily dissolvable

Calcium Hydroxide - partially soluble

Magnesium Hydroxide - insoluble

24
Q

How does the solubility of sulphates change down the group?

A

Less soluble down the group

25
Q

How would the full equation for formation of a sulphate precipitate be written?

A

XCl2(aq) + Na2SO4 > 2NaCl + XSO4

26
Q

How would the ionic equation for the formation of a sulphate precipitate be written?

A

X^2+(aq) + SO4^2-(aq )> XSO4 (s)

27
Q

How is a sulphate tested for?

A

Add Hydrochloric acid and white precipitate should form

28
Q

How would insoluble salt be removed from a solution?

A

Filtration

Wash with distilled water to remove soluble impurities and then dry on filter paper.

29
Q

What are spectator ions?

A

Do not change state or oxidation number