2) Reactivity Trends

Question 1

Use ‘Reactivity Trends’ card to test knowledge of the reaction between a group 2 metal and oxygen.

Answer 1

Rate knowledge 1-5.

Question 2

Use ‘Reactivity Trends’ card to test knowledge of the reaction between a group 2 metal and water.

Answer 2

Rate knowledge 1-5.

Question 3

What is formed when an acid reacts with a metal?

Answer 3

Salt + Hydrogen.

Question 4

State and explain the trend in first and second ionisation energies of group 2 elements down the group.

Answer 4

The ionisation energies decrease down the group because the attraction between the nucleus and the outer electrons and decreases as a result of increased atomic radius and increased shielding.

Question 5

Use ‘Reactivity Trends’ card to test knowledge of the reaction between a group 2 oxides and water.

Answer 5

Rate knowledge 1-5.

Question 6

What is the trend in the solubility of group 2 hydroxides?

Answer 6

• Solubility increases.
• pH increases.
• Alkalinity increases.

Question 7

What is calcium hydroxide used as in agriculture?

Answer 7

To neutralise acidic soil.

Question 8

What are magnesium hydroxide and calcium carbonate both commonly used as?

Answer 8

‘Antacids’ in treating indigestion.

Question 9

Explain the trend in boiling points down the halogens.

Answer 9

• More electrons.
• Stronger London forces.
• More energy required to break the intermolecular forces.
• Boiling point increases.

Question 10

Explain the trend in reactivity down the halogens.

Answer 10

• Atomic radius increases.
• More inner shells so shielding increases.
• Less nuclear attraction to capture an electron from another species.
• Reactivity decreases.

Question 11

What colour is Cl2 in water?

Answer 11

Pale green.

Question 12

What colour is Br2 in water?

Answer 12

Orange.

Question 13

What colour is I2 in water?

Answer 13

Brown.

Question 14

What colour is Cl2 in cyclohexane?

Answer 14

Pale green.

Question 15

What colour is Br2 in cyclohexane?

Answer 15

Orange.

Question 16

What colour is I2 in cyclohexane?

Answer 16

Violet.

Question 17

What is the reaction of Cl-(aq) with Br2?

Answer 17

No reaction.

Question 18

What is the reaction of Cl-(aq) with I2?

Answer 18

No reaction.

Question 19

What is the reaction of Br-(aq) with Cl2?

Answer 19

Orange colour from Br2 formation.

Question 20

What is the reaction of Br-(aq) with I2?

Answer 20

No reaction.

Question 21

What is the reaction of I-(aq) with Cl2?

Answer 21

Violet colour from I2 formation.

Question 22

What is the reaction of I-(aq) with Br2?

Answer 22

Violet colour from I2 formation.

Question 23

Define disproportionation.

Answer 23

Oxidation and reduction of the same element.

Question 24

Use ‘Reactivity Trends’ card to test knowledge of the reaction between chlorine and water.

Answer 24

Rate knowledge 1-5.

Question 25

Use 'Reactivity Trends' card to test knowledge of the reaction between chlorine and cold, dilute, aqueous sodium hydroxide.

Answer 25

Rate knowledge 1-5.

Question 26

What is the benefit of using chlorine in water treatment?

Answer 26

Kills bacteria.

Question 27

What is the risk of using chlorine in water treatment?

Answer 27

Chlorine gas is toxic.

Question 28

What is the sulfate test?

Answer 28

A white precipitate is formed when Ba2+ ions are added to a solution of sulfate ions.

Question 29

What is the carbonate test?

Answer 29

White precipitate turns the limewater milky.

Question 30

What is the colour of the precipitate formed when Cl- ions react with silver ions? Also, give the solubility of the solution in ammonia.

Answer 30

- Colour of precipitate: White | - Solubility in NH3: Soluble in dilute NH3.

Question 31

What is the colour of the precipitate formed when Br- ions react with silver ions? Also, give the solubility of the solution in ammonia.

Answer 31

- Colour of precipitate: Cream | - Solubility in NH3: Soluble in conc. NH3.

Question 32

What is the colour of the precipitate formed when I- ions react with silver ions? Also, give the solubility of the solution in ammonia.

Answer 32

- Colour of precipitate: Yellow | - Solubility in NH3: Insoluble in conc. NH3.

Question 33

What is the test for the ammonium ion, NH4+?

Answer 33

Reaction with warm NaOH to form NH3.

Question 34

Describe what you would expect to see when magnesium ribbon is added to an excess of dilute hydrochloric acid.

Answer 34

- Fizzes/bubbles. | - Mg dissolves.

Question 35

Describe one difference you might observe if strontium, instead of magnesium, was reacted with dilute hydrochloric acid.

Answer 35

Quicker/more vigorous reaction.

Question 36

Describe and explain the trend, down the group, in the reactivity of the Group 2 elements with water.

Answer 36

- Reactivity increases down the group. - Atomic radii increase. - There is more shielding. - Nuclear attraction decreases. - Easier to remove outer electrons.

Question 37

Explain, in terms of electrons, what is meant by oxidation.

Answer 37

Loss of electrons.

Question 38

Old samples of magnesium oxide become contaminated with magnesium carbonate. Suggest how this contamination takes place.

Answer 38

MgO has reacted with CO2.

Question 39

Explain, in terms of electrons, what is meant by reduction.

Answer 39

Gain of electrons.