EL - Group 2

Question 1

What do group 2 elements react with?

Answer 1

Water and oxygen.

Question 2

When group 2 elements react, what charge ions do they form?

Answer 2

2+

Question 3

When group 2 metals react with water, what do they produce?

Answer 3

Hydroxides and hydrogen.

Question 4

What do group 2 elements burn in oxygen to produce?

Answer 4

Solid white oxides.

Question 5

What is the trend in reactivity of group 2 metals?

Answer 5

They get increasingly reactive down the group because the outermost electrons are further from the nucleus, and so more easily lost.

Question 6

Why do the group 2 metals get more reactive as you go down the group?

Answer 6

They get increasingly reactive down the group because the outermost electrons are further from the nucleus, and so more easily lost.

Question 7

What are group 2 oxides and hydroxides?

Answer 7

Bases.

Question 8

Because group 2 oxides and hydroxides are bases, what does this mean they do?

Answer 8

Form alkaline solutions in water.

Neutralise acids.

Question 9

Why do group 2 oxides and hydroxides form alkaline solutions in water?

Answer 9

The oxides of group 2 metals react readily with water to form metal hydroxides, which dissolve. The hydroxide ions, OH-, make the these solutions strongly alkaline.

Question 10

How do group 2 oxides and hydroxides neutralise acids?

Answer 10

Because they’re bases both the oxides and hydroxides neutralise dilute acids, forming solutions of the corresponding salts.

Question 11

Which group 2 metal oxide doesn’t form an alkaline solution in water and why?

Answer 11

Magnesium oxide because it only reacts slowly and the hydroxide isn’t very soluble.

Question 12

How does the strength of the alkaline solutions formed by group 2 metal oxides and hydroxides change as you go down the group and why?

Answer 12

The oxides form more strongly alkaline solutions as you go down the group because the hydroxides get more soluble.

Question 13

What pH does calcium hydroxide have?

Answer 13

12

Question 14

What do the solubility trends of group 2 elements depend on?

Answer 14

The compound anion.

Question 15

How does solubility of compounds of group 2 elements that contain singly charged negative ions change as you go down the group?

Answer 15

Increase in solubility as you go down the group.

Question 16

How does solubility of compounds of group 2 elements that contain doubly charged negative ions change as you go down the group?

Answer 16

Decrease in solubility as you go down the group.

Question 17

Rank these from least to most soluble:
Calcium Hydroxide
Strontium Hydroxide
Magnesium Hydroxide
Barium Hydroxide

Answer 17

LEAST:
Magnesium Hydroxide
Calcium Hydroxide
Strontium Hydroxide
Barium Hydroxide
MOST:

Question 18

Rank these from least to most soluble:
Calcium Carbonate
Strontium Carbonate
Magnesium Carbonate
Barium Carbonate

Answer 18

LEAST:
Barium Carbonate
Strontium Carbonate
Calcium Carbonate
Magnesium Carbonate
MOST:

Question 19

What are group 2 compounds like magnesium hydroxide, which have very low solubilities, said to be?

Answer 19

Sparingly soluble.

Question 20

What do group 2 carbonates decompose to form?

Answer 20

Carbon dioxide and metal oxide.

Question 21

When do group 2 carbonates form carbon dioxide and a metal oxide?

Answer 21

When they decompose.

Question 22

What is thermal decomposition?

Answer 22

When a substance breaks down (decomposes) when heated.

Question 23

How does the volume of carbon dioxide produced during decomposition of group 2 carbonates change as you go down the group?

Answer 23

Volume decreases as you go down the group as the Mr of the metal gets bigger, so a smaller number of metal carbonate moles is contained on the same mass.

Question 24

Finish the statement:

The more thermally stable a substance is…

Answer 24

…the more heat it will take to break down.

Question 25

How does thermal stability change as you go down group 2?

Answer 25

Increases down the group.

Question 26

What type of ion are carbonate ions?

Answer 26

Large anions.

Question 27

How can carbonate ions be made unstable?

Answer 27

By the presence of a cation such as a group 2 metal ion.

Question 28

What does the presence of a cation do to a carbonate ion?

Answer 28

Makes it unstable.

Question 29

How can a cation make large anions unstable?

Answer 29

The cation draws the electrons on the carbonate ion towards itself (it polarises it). This distorts the carbonate ion.

Question 30

Finish the statement regarding cations making anions unstable:
The greater the distortion…

Answer 30

… the less stable the carbonate ion.

Question 31

What charge do anions have?

Answer 31

negative

Question 32

What charge do cations have?

Answer 32

positive

Question 33

Which cause less distortion, large cations or small cations?

Answer 33

Large cations.

Question 34

Why do large cations cause less distortion than small cations?

Answer 34

Because they have a lower charge density.

Question 35

What is charge density?

Answer 35

The charge on the ion relative to its volume.

Question 36

Explain the trend in distortion and stability that occurs as you go down group 2:

Answer 36

Further down the group, the larger the cations, the less distortion caused and the more stable the carbonate anion.

Question 37

Which is less stable and why, magnesium carbonate or barium carbonate?

Answer 37

Magnesium ions polarise carbonate ions more than barium ions do, meaning magnesium carbonate is less stable.

Question 38

How does charge density change as you go down group 2?

Answer 38

Decreases down the group.