2) Reactivity Trends Flashcards
Use ‘Reactivity Trends’ card to test knowledge of the reaction between a group 2 metal and oxygen.
Rate knowledge 1-5.
Use ‘Reactivity Trends’ card to test knowledge of the reaction between a group 2 metal and water.
Rate knowledge 1-5.
What is formed when an acid reacts with a metal?
Salt + Hydrogen.
State and explain the trend in first and second ionisation energies of group 2 elements down the group.
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.
Use ‘Reactivity Trends’ card to test knowledge of the reaction between a group 2 oxides and water.
Rate knowledge 1-5.
What is the trend in the solubility of group 2 hydroxides?
- Solubility increases.
- pH increases.
- Alkalinity increases.
What is calcium hydroxide used as in agriculture?
To neutralise acidic soil.
What are magnesium hydroxide and calcium carbonate both commonly used as?
‘Antacids’ in treating indigestion.
Explain the trend in boiling points down the halogens.
- More electrons.
- Stronger London forces.
- More energy required to break the intermolecular forces.
- Boiling point increases.
Explain the trend in reactivity down the halogens.
- Atomic radius increases.
- More inner shells so shielding increases.
- Less nuclear attraction to capture an electron from another species.
- Reactivity decreases.
What colour is Cl2 in water?
Pale green.
What colour is Br2 in water?
Orange.
What colour is I2 in water?
Brown.
What colour is Cl2 in cyclohexane?
Pale green.
What colour is Br2 in cyclohexane?
Orange.
What colour is I2 in cyclohexane?
Violet.
What is the reaction of Cl-(aq) with Br2?
No reaction.
What is the reaction of Cl-(aq) with I2?
No reaction.
What is the reaction of Br-(aq) with Cl2?
Orange colour from Br2 formation.
What is the reaction of Br-(aq) with I2?
No reaction.
What is the reaction of I-(aq) with Cl2?
Violet colour from I2 formation.
What is the reaction of I-(aq) with Br2?
Violet colour from I2 formation.
Define disproportionation.
Oxidation and reduction of the same element.
Use ‘Reactivity Trends’ card to test knowledge of the reaction between chlorine and water.
Rate knowledge 1-5.
Use ‘Reactivity Trends’ card to test knowledge of the reaction between chlorine and cold, dilute, aqueous sodium hydroxide.
Rate knowledge 1-5.
What is the benefit of using chlorine in water treatment?
Kills bacteria.
What is the risk of using chlorine in water treatment?
Chlorine gas is toxic.
What is the sulfate test?
A white precipitate is formed when Ba2+ ions are added to a solution of sulfate ions.
What is the carbonate test?
White precipitate turns the limewater milky.
What is the colour of the precipitate formed when Cl- ions react with silver ions? Also, give the solubility of the solution in ammonia.
- Colour of precipitate: White
- Solubility in NH3: Soluble in dilute NH3.
What is the colour of the precipitate formed when Br- ions react with silver ions? Also, give the solubility of the solution in ammonia.
- Colour of precipitate: Cream
- Solubility in NH3: Soluble in conc. NH3.
What is the colour of the precipitate formed when I- ions react with silver ions? Also, give the solubility of the solution in ammonia.
- Colour of precipitate: Yellow
- Solubility in NH3: Insoluble in conc. NH3.
What is the test for the ammonium ion, NH4+?
Reaction with warm NaOH to form NH3.
Describe what you would expect to see when magnesium ribbon is added to an excess of dilute hydrochloric acid.
- Fizzes/bubbles.
- Mg dissolves.
Describe one difference you might observe if strontium, instead of magnesium, was reacted with dilute hydrochloric acid.
Quicker/more vigorous reaction.
Describe and explain the trend, down the group, in the reactivity of the Group 2 elements with water.
- Reactivity increases down the group.
- Atomic radii increase.
- There is more shielding.
- Nuclear attraction decreases.
- Easier to remove outer electrons.
Explain, in terms of electrons, what is meant by oxidation.
Loss of electrons.
Old samples of magnesium oxide become contaminated with magnesium carbonate. Suggest how this contamination takes place.
MgO has reacted with CO2.
Explain, in terms of electrons, what is meant by reduction.
Gain of electrons.
