Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

IGCSE Chemistry - Inorganic Chemistry (Alkali Metals - Reactivity Series) > Alkali Metals > Flashcards

Alkali Metals Flashcards

1
Q

What sort of solutions do alkali metals form when they react with water and what pH range is that solution?

A

They form alkaline solutions with a pH greater than 7 (8-14).

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

What are the group 1 metals (in order of reactivity?)

A

Lithium, Sodium, Potassium, Rubidium, Caesium and Francium

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

Why do alkali metals share similar characteristic chemical properties?

A

Alkali metals share similar characteristic chemical properties because they each have one electron in their outermost shell.

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

What are some properties of alkali metals?

A

They are soft (can be cut with a knife), knife, they have relatively low densities and low melting points and are very reactive (they only need to lose one electron to become highly stable).

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

What provides evidence for categorizing alkali metals into the same chemical family?

A

The reaction of the group 1 metals with water provides evidence for categorising these elements into the same chemical family.

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

What is the general word and chemical equation for alkali metals’ reaction with water? (Include state symbols)

A

group 1 metal + water ⟶ metal hydroxide + hydrogen

2M (s) + 2H2O (l) ⟶ 2MOH (aq) + H2 (g)

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

What are the common characteristics
across all of the hydroxides formed?

A

The common characteristic across all the hydroxides formed is that they all have the same general formula and are colourless, aqueous solutions.

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

Why are metals so named?

A

The metals are so named because they form alkalis in water.

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

What provides evidence of trends within group 1?

A

The differences between the reactions of the group 1 metals with water and oxygen provide evidence of trends within the group.

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

How do the reactions of alkali metals with water change as you descend the group?

A

The reactions of the alkali metals with water get more vigorous as you descend the group.

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

How does lithium react with water?

A

It is a relatively slow reaction, Lithium floats, fizzes, keeps its shape as it reacts and gets smaller and disappears. However, lithium does not melt.

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

How does Sodium react with water?

A

Floats, fizzes, melts into a ball (large amounts of heat is given off to melt the sodium), hydrogen released catches fire which causes the ball to dash around the surface and disappears leaving a white trail.

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

How does Potassium react with water?

A

Floats, fizzes, melts into a ball that dashes around the surface and enough heat is released so hydrogen burns with a lilac coloured flame

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

What do alkali metals form when they react with oxygen in the air?

A

The alkali metals react with oxygen in the air forming metal oxides.

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

Why do alkali metals tarnish when exposed to the air?

A

Alkali metals tarnish when exposed to air because they react with oxygen in the air forming metal oxides.

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

Describe the metal oxide produced/

A

The metal oxide produced is a dull coating which covers the surface of the metal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the correlation
between the rate that the metal tarnishes and the position of the metal in the group?

A

The metal tarnish more rapidly as you go descend the group.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe the properties and physical trends in alkali metals

A

The alkali metals are soft and easy to cut (get softer as you move down the group), first three alkali metals are less dense than water (densities increases as you descend the group), all have relatively low melting points (decreases as you move down the group)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why do melting points and boiling points decrease as you move down the group 1?

A

Melting and boiling points decrease as you move down the group, due to decreasing attractive forces between outer electrons and positive ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are trends?

A

Trends are patterns of behaviour that change as you go down a group or across a period.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What can we say about Rb, Cs and Fr’s reactions with air and water in regards to the group 1 trends?

A

Following these trends, we can say that Rubidium, caesium and francium will react even more vigorously with air and water than the first three alkali metals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Using the information given in the trends, what could we predict about rubidium?

A

Rubidium would be a soft grey solid, appear shiny when freshly cut, more dense than potassium and has a lower melting point than potassium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When asked in the exam, what would be good words to make predictions about how rubidium would be expected to react with water?

A

Explosively and violently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How does reactivity change as you descend group 1?

A

The reactivity of the group 1 metals increases as you go down group 1.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Explain, in terms of electronic configurations, the trend in reactivity in group 1.

A

When a group 1 element reacts its atoms only need to lose electron, as there is only 1 electron in the outer shell. The next shell down automatically becomes the outermost shell and since it is already full, a group 1 ion gains a noble gas configuration. As you go down group 1, the number of shells increase by 1. Meaning that outermost electron gets further away from the nucleus and therefore there are weaker forces of attraction between the outermost electron and nucleus. Less energy is required to overcome these forces of attraction as it gets weaker so the outer electron is lost more easily. So, the alkali metals get more reactive as you descend the group.

26
Q

How many electrons are in the alkali metals’ outermost shell?

A

One

27
Q

Why are alkali metals stored under oil?

A

Alkali metals are stored under oil as they react quickly with oxygen, therefore to prevent oxygen from reaching the surface of the bare metal.

28
Q

How does Lithium react with air?

A

Lithium burns in air with a red flame to form lithium oxide.

29
Q

How does Sodium react with air?

A

Sodium burns in air with an orange flame to form Sodium oxide.

30
Q

What is different about Potassium’s reaction with oxygen than with the first two elements in group 1?

A

Potassium reacts with oxygen to form Potassium superoxide, while the first two elements react with oxygen to form just a metal oxide.

31
Q

How does Potassium react with oxygen?

A

Potassium burns in oxygen with a lilac coloured flame to form Potassium superoxide.

32
Q

How does Rubidium react with oxygen?

A

Rubidium burns in air to produce an orange/yellow or even dark brown superoxide.

33
Q

How does Caesium react with oxygen?

A

Caesium burns in air to produce an orange/yellow superoxide.

34
Q

Alkali metals react with oxygen to form…

A

Oxides/Superoxides (in K, Rb and Cs’s case)

35
Q

Alkali metals react with water to form…

A

Metal hydroxides and hydrogen gas

36
Q

Alkali metals react with acid to form…

A

A salt and hydrogen gas

37
Q

Alkali metals react with group 7 to form…

A

A salt

38
Q

What is Lithium used for?

A

Batteries

39
Q

What is Sodium used for?

A

Salt and street lamps

40
Q

What is Potassium used for?

A

Used as a Fertiliser and for gun powder

41
Q

What is Rubidium used for?

A

To locate tumours (cancer)

42
Q

What are the most reactive metals?

A

Alkali metals

43
Q

Describe alkali metals’ compounds when dissolved in water.

A

They are colourless when dissolved in water.

44
Q

What is the word equation for Lithium’s reaction with oxygen?

A

lithium + oxygen -> lithium oxide

45
Q

What is the balanced chemical equation for Lithium’s reaction with oxygen? (Include state symbols)

A

4Li(s) + O2 (g) -> 2Li2O(s)

46
Q

What is the word equation for Sodium’s reaction with oxygen?

A

Sodium + Oxygen - > Sodium oxide

47
Q

What is the balanced chemical equation for Sodium’s reaction with oxygen? (Include state symbols)

A

4Na (s) + O2(g) - > 2Na2O(s)

48
Q

What is the word equation for Potassium’s reaction with oxygen?

A

Potassium + Oxygen -> Potassium superoxide

49
Q

What is the balanced chemical equation for Potassium’s reaction with oxygen? (Include state symbols)

A

K(s)+ O2(g) -> KO2 (s)

50
Q

What state of matter are oxides/superoxides?

A

Solids

51
Q

How can we identify which alkali metal is reacting with oxygen? And explain the method

A

By doing a flame test; first have a small piece of wire loop, dip it into the solution, then hold in the loop in the flame which will then show the colour of the alkali metal.

52
Q

What is the charge of group 1 metals?

A

1+

53
Q

Write the symbol for a Lithium ion

A

Li+

54
Q

Write the symbol for a Sodium ion

A

Na+

55
Q

Write the symbol for a Potassium ion

A

K+

56
Q

What does more bubbles when alkali metals react with water mean?

A

More​ ​bubbles​ ​with​ ​reaction​ ​with​ ​water, the more​ ​vigorous​ ​a reaction is and therefore​ the​ ​more​ ​reactive
alkali​ ​metal is.

57
Q

How do the reactions of lithium, sodium and potassium with water provide evidence for their recognition as a family of elements?

A

These similarities in the reactions provide evidence that the 3 metals are in the same group of the Periodic Table (i.e. have the same number of electrons in their outer shell).

58
Q

How do the differences between the reactions of lithium, sodium and potassium with air and water provide evidence for the trend in reactivity in Group 1?

A

When the group 1 metals react with air they oxidise, this shows a similar trend in reactivity as we go down the group of the Periodic Table. Therefore, as we go down group 1 (increasing atomic number), the elements become more reactive

59
Q

Why does Potassium sulfate have a high melting point?

A

There is an electrostatic attraction between oppositely charged ions; this attraction between ions is strong. Therefore, it requires a large amount of energy to overcome these forces.

60
Q

Give a test to show that lithium fluoride contains lithium ions.

A

Perform a flame test; if the flame is red; then lithium ions are present.

61
Q

What is the general formula between group 1 metals and group 7 halogens?

A

The formula is: 2M + X2 → 2MX

IGCSE Chemistry - Inorganic Chemistry (Alkali Metals - Reactivity Series) (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions