Group 7 Flashcards
Explain the trend in Atomic Radius as you go down group 7
Increases due to more electron shells; bigger atoms
Explain the trend in electronegativity as you go down group 7
Decreases as there are bigger atoms, more shielding and weaker attraction between nucleus and outer electrons
Explain the trend in M.P/B.P as you go down group 7
Increases as there are more Van Der Waals forces as the molecules get bigger
Explain the trend in F.I.E down group 7
Decreases as atoms get bigger, more shielding, weaker attraction from nucleus to electron in outer shell
Explain the trend in Oxidising strength as you gown the group 7
It decreases as it becomes harder to gain an electron because atoms are larger and there is more shielding
State what type of reaction chlorine + water is… And what happens in sunlight
It is a Disproportionation Reaction as Chlorine is both oxidised and reduced
Cl2 + H2O HClO + HCl
In sunlight:
Cl2 + H2O 2H+ + 2Cl- + 1/2O2
State 3 Advantages for treating water with chlorine
- Destroys Microorganisms that cause disease
- last long so it reduces build up of bacteria later in the supply
- reduces growth of algae that discolours water and gives a bad smell
State 3 disadvantages for treating water with chorine
- It is toxic and irritates respiratory system
- can cause severe chemical burns
- has been linked to cause cancer
HOWEVER, IT MUST BE DONE SO THERE IS NO CHOLERA EPIDEMIC
How do you make bleach and what type of reaction is it and state 2 uses.
It is a Disproportionation Reaction.
Cl2 + 2NaOH –> NaCl + NaClO + H2O
Uses:
Disinfect bacteria
Toiletries
State the test to identify Metal halides with Silver ions + further tests to distinguish between them
Add dilute Nitric Acid to remove carbonate/hydroxide impurities. Then add silver nitrate to the halide ion
- F- = no ppt
- Cl- = White ppt
- Br- = Cream ppt
- I- = Yellow ppt
Add dilute ammonia solution which will change Cl because it’s soluble whereas Br + I are insoluble and then add conc. Ammonia and Br will dissolve leaving I as insoluble
State the reaction, observation, reaction type for Cl with conc. Sulfuric Acid
The products will be HCl and you will observe Steamy Fumes and it’s an Acid Base reaction
State the products, observation, reaction type for the reaction between Br and Conc. sulfuric acid
HBr will be produced producing Steamy Fumes (Acid Base reaction)
Br2 will be produced producing brown fumes (Oxidation of Br)
SO2 will be produced producing Colourless Gas/ Choking (Reduction of H2SO4)
State the products, Observation, Reaction Type for I reacting with Conc. Sulfuric Acid
HI will be produced producing Steamy fumes (Acid Base reaction)
I2 will be produced producing purple fumes (Oxidation of I)
SO2 will be produced producing Colourless Gas/choking (Reduction of H2SO4)
S will be produced producing a yellow solid (Reduction of H2SO4)
H2S will be produced producing bad egg smell (Reduction of H2SO4)
What is observed when Cl2 reacts with Br-?
Orange solution
What is observed when Cl2 reacts with I-?
Brown Solution
