Chapter 8 Flashcards
What colour are Group 2 compounds?
White or colourless
What are Group 2?
Alkaline earth metals
Are group 2 hard or soft metals?
Soft metals with low melting points
Are group 2 reactive or non reactive?
Reactive so usually found in compounds
What do Group 2 react with?
They undergo REDOX reactions with oxygen, water and dilute acids
What are Group 2 known as?
The halogens
What happens to Group 2 electron configurations during a reaction?
They react by loosing their outer 2 electrons to form 2+ ions
What type of agents are group 2 elements? What does that mean?
Reducing agents: a substance that causes another species to be reduced
What is produced when a Group 2 metal reacts with water?
They form an alkaline hydroxide and hydrogen gas
What can be observed when Group 2 elements react with water?
Fizzing/ effervescence and the solid dissapears
How does reactivity change down the group?
Reactivity increases down Group 2
What is observed during the REDOX reaction with oxygen and a halogen?
Burns with a bright white flame and white powder is produced
What is formed and seen when a halogen reacts with a dilute acid?
A salt is formed in addition to hydrogen gas, fizzing/ effervescence is seen and the solid disspears
How is shielding and atomic radius effected down Group 2?
They increase
How is nuclear attraction effected down Group 2?
It decreases
How is reactivity effected down Group 2?
Increases
How is the first ionisation energy effected down group 2?
Decreases
What is produced when group 2 oxides react with water?
Hydroxides
What is the typical pH of a Group 2 oxide?
Between pH 10-12
Are Group 2 oxides soluble? What happens when the solution becomes saturated?
Only slightly in water, once saturated a solid white precipitate forms
How is solubility in water effected by going down Group 2?
Increases down the group
How is alkalinity effected going down Group 2?
Increases
How is pH effected by going down Group 2?
Increases
What is a use for calcium hydroxide?
Reduce soil acidity
What is a use for magnesium hydroxide?
Neutralising excess HCl in the stomach
What is the outermost shell configuration for halogens?
ns2np5
Are halogens atomic or diatomic?
All diatomic
How stable are halogen as a element?
Very unstable to they are mostly found in metal compounds
What temperature can halogens be found?
Room temperature
What is the room temperature appearance of F2?
Pale yellow gas
What is the room temperature appearance of Cl2?
Pale green gas
What is the room temperature appearance of I2?
Red- Brown liquid
What is the room temperature appearance of Br2?
Shiny grey-black solid
What is the room temperature appearance of At2?
Never been seen
How are London forces effected down group 7?
Increased in strength
How is the energy required to break intermolecular bonds effected down group 7?
The bonds are stronger so more energy is required
How is boiling point effected down group 7?
Increased
How is the number of electrons effected down group 7?
Increased
What colour is solutions of halogens?
They all form different colours
Are halogens polar?
No they are non-polar so more soluble in non polar solvents like alkanes
What is the colour of Chlorine in water?
Very pale yellow
What is the colour of Bromine in water?
Orange
What is the colour of Iodine in water?
Brown
What is the colour of Chlorine in an alkane?
Pale Green
What is the colour of Bromine in an alkane?
Orange
What is the colour of Iodine in an alkane?
Violet
Why do two layers form if water are cyclohexane are mixed?
They are immiscible
What type of agent are halogen and what does this mean?
Halogen react by gaining an electron so are oxidising agents: they oxidise another species
Why does the halogens oxidising agent decrease down group 7?
Down the group the atomic radius and shielding increase, nuclear attraction decreases so ability to gain an electron decreases
Define disproportionation
A single element is both oxidised and reduced in the same reaction
What colour is the precipitate produced by AgCl (s) and silver nitrate?
White
What colour is the precipitate produced by AgBr (s) and silver nitrate?
Cream
What colour is the precipitate produced by AgI (s) and silver nitrate?
Yellow
What 4 things can you observe during a reaction?
- Effervescence
- Colour change
- Precipitates
- Identification
How can SO4 2- be identified?
By precipitation with Ba2+ (aq)
How can CO3 2- be identified?
By reaction with H+ (aq) to form CO2(g)
How can Cl-, Br-, I- be identified?
By precipitation with Ag+ (aq) / solubility in NH3 solution
How can NH4+ be identified?
Warm with NaOH(aq) to form NH3
What test can be used to identify the Carbonate ion, CO3 2- ?
Add a few drops of dilute nitric acid
Observe effervescence due to CO2 gas
What test can be used to identify the Sulfate ion, SO4 2-?
Add an equal volume of barium nitrate (aq)
Observe a white precipitate of barium nitrate
What test can be used to identify the Chloride ion, Cl-?
Add an equal volume of silver nitrate
(aq)
observe a white precipitate of silver chloride ( soluble in ammonia solution)
What test can be used to identify the Bromide ion, Br-?
Add an equal volume of silver nitrate (aq)
Observe a cream precipitate of silver bromide (soluble in concentrated ammonia solution)
What test can be used to identify the Iodide ion, I-?
Add an equal volume of aqueous silver nitrate
Observe a yellow precipitate of silver iodide ( in both dilute and concentrated ammonia solution)
What test can be used to identify the Ammonium ion, NH4+?
Warm with dilute sodium hydroxide and test any gas given off with damp red litmus paper.
Observe gas (ammonia) which turns litmus paper blue
Why must some ion tests be carried out in a specific order?
In order to avoid false positive results
What are the for ion tests and what order must you carry them out in?
- Carbonate, CO3 2-
- Sulphate, SO4 2-
- Halides, Cl-, Br-, I-
- Ammonium ion test
