OCR A-Level Chemistry: Chapter 8 - Reactivity Trends
This flashcard set focuses on redox behavior and trends within Group 2 elements. It defines reducing agents, identifies their common group, and outlines how reactivity changes down the group—ideal for mastering redox and periodic trends.
What is a reducing agent?
A species that donates it’s electrons to another species, thereby reducing that species.
Key Terms
What is a reducing agent?
A species that donates it’s electrons to another species, thereby reducing that species.
Which group are reducing agents commonly found?
Group 2
What is the trend in reactivity down group 2?
Reactivity increases.
Explain the trend of reactivity down group 2
Increased atomic radius and shielding effect so ionisation energies decrease. Therefore it’s easier to lose electrons.
What are the products of a group 2 element reacting with water?
Metal hydroxide and hydrogen
What is the product of a group 2 element reacting with oxygen?
Metal oxide
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| Term | Definition |
|---|---|
What is a reducing agent? | A species that donates it’s electrons to another species, thereby reducing that species. |
Which group are reducing agents commonly found? | Group 2 |
What is the trend in reactivity down group 2? | Reactivity increases. |
Explain the trend of reactivity down group 2 | Increased atomic radius and shielding effect so ionisation energies decrease. Therefore it’s easier to lose electrons. |
What are the products of a group 2 element reacting with water? | Metal hydroxide and hydrogen |
What is the product of a group 2 element reacting with oxygen? | Metal oxide |
What is the trend of solubility down group 2? | Increases |
Explain the trend of solubility down group 2 | Down the group, the solution has a greater concentration of OH-. |
Given that group 2 oxides, hydroxides and carbonates neutralise acids, what can they be referred to as? | Bases |
Given that most group 2 oxides, hydroxides and carbonates are soluble in water, what are they also besides bases? | Alkalis |
What is the use of calcium hydroxide in agriculture? | Increases the pH of acidic soils. Ca(OH)(2) + 2H+ -> Ca2+ + 2H(2)O |
How are group 2 compounds used in medicine? | Used in indigestion tablets as antacids, often a suspension of a metal hydroxide in water. |
What is another name for group 2? | Alkaline Earth Metals |
What is another name for group 7? |
|
What is the trend in boiling point down group 7? |
|
Explain the trend in boiling point down group 7 | More electrons, |
What is the trend in reactivity down group 7? | Reactivity decreases |
Explain the trend in reactivity down group 7 | Atomic radius increases, More inner shells, Shielding increases, Nuclear attraction decreases, Reactivity decreases. |
What do more reactive halogens do to less reactive halide ions? | Displace them |
What can displacement reactions be used to identify? | Which halide is present in solution. |
Which compound is used to test for halides? | Silver nitrate solution |
How can the results for a halide test be further tested? | Solubility in ammonia solution |
What is disproportionation? | A redox reaction in which the same element is both oxidised and reduced. |
Describe the test for carbonates | Carbonates react with acids to form carbon dioxide gas. |
Describe the test for sulphates | Aqueous barium ions are added to the solution. If a white precipitate forms, there is a sulphate. |
In the halide tests, what happens to chloride with silver nitrate and then ammonia | Silver nitrate - white precipitate | Ammonia - soluble in dilute ammonia |
In the halide tests, what happens to bromide with silver nitrate and then ammonia | Silver nitrate - cream precipitate | Ammonia - soluble in concentrated ammonia |
In the halide tests, what happens to iodide with silver nitrate and then ammonia | Silver nitrate - yellow precipitate | Ammonia - insoluble in concentrated ammonia |
What is the correct order for these anion tests? | Carbonate test, sulphate test, halide test |
Why is this the correct order for anion tests carbonate, sulphate, halide? | Carbonates also form a white precipitate in the sulphate test but not vice versa. |
Describe the test for ammonium ions | Add aqueous NaOH to the solution, |