Chapter 8 - Reactivity trends Flashcards
(43 cards)
What is another name for group 2 ?
Alkaline earth metals
What is a reducing agent ?
- A species that donates its electrons to another species, thereby reducing that species
- It is known as an electron donor
Which group are reducing agents commonly found ?
Group 2
What is the trend in reactivity down group 2 ?
Reactivity increases as you go down group 2
Explain why reactivity increases as you go down group 2
- As you go down the group the atomic radius and shielding effect increase so ionisation energies decrease
- Therefore it is easier to lose electrons and they get more reactive down the group
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 like down group 2 ?
Solubility increases as you go down the group
Explain why solubility increases as you go down group 2
As you go down the group the solution has a greater concentration of hydroxide ions
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 as antacids in indigestion tablets
- They are often a suspension of a metal hydroxide in water
- Milk of magnesia is an example of this
What is the trend in boiling point down group 7 ?
The boiling point down the group increases
Explain why the boiling point increases down group 7
- There are more electrons as you go down the group
- Therefore stronger london forces are present
- More energy is required to break these intermolecular forces
- Therefore the boiling point increases down the group
What is the trend in reactivity down group 7 ?
Down the group the reactivity decreases
Explain why reactivity decreases as you go down group 7
- The atomic radius increases
- More inner shells so there is a greater shielding effect
- Nuclear attraction therefore decreases and it is harder to gain an electron
- This leads to reactivity decreasing down the groups
You have to remember that group 7 elements need to gain an electron, not lose one
What do more reactive halogens do to less reactive halogens ?
More reactive halogens displace less reactive halogen ions
What can chlorine displace ?
Iodine and bromine
What can bromine displace ?
Iodine only
What can iodine displace ?
It can’t displace chlorine or bromine
What can displacement reactions be used to identify ?
It allows you to identify which halide is present in the solution
Which compound is used to test for halides ?
Silver nitrate solution, AgNO3
How can the results for a halide test be further tested ?
For solubility in ammonia solution
