Chemistry-2.3: Group 7

What happens to electronegativity down the group

What happens to electronegativity down the group

• It decreases due to the atomic radius increasing and there is more shielding and they are further from the nucleus.

What happens to boiling point down the group

• It increases due to the increasing strength of the VDW forces

What happens to oxidising ability down the group

Oxidising ability decreases down the group

• A halogen will displace a halide if the halide is below it in the periodic table

What is the trend in reducing ability as you go down the group

• it gets stronger due to: the ions getting bigger so the electrons are further from the nucleus, there are extra inner electrons (more shielding)

• further down the group = easier losing electrons + greater reducing ability

make flashcards on the equations of reacting w sulfuric acid

revise

How do you test for halide ions with silver nitrate (mnemonic)

• dilute nitric acid to remove impurities

• add silver nitrate

• Halides want carrot cake because you insisted

What is the trend of solubility of silver halides in ammonia?

• solubility decreases down the group

Why is the silver nitrate solution acidified

• react with / remove (an)ions that would interfere with the test

• prevent the formation of other silver precipitates

• remove (other) ions that react with the silver nitrate

• remove carbonate / hydroxide / sulfite (ions)

Why is the ammonia solution added to the silver nitrate solution

So you can be extra sure of the halide formed as they all have different solubilities

What happens when you mix chlorine and water?

• It undergoes disproportionation ending with a mixture of chloride ions and chlorate(I) ions

• In sunlight (UV) chlorine decomposes water to form chloride ions and oxygen

What are the advantages of using chlorine in water treatment?

• it kills disease-causing microorganisms and bacteria

• prevents the growth of algae eliminating bad tastes,smells or discolouration

• some chlorine persists and prevents reinfection further down the supply

What are the disadvantages of using chlorine in water treatment?

• Accidents with chlorine are serious: chlorine gas is very harmful-irritates respiratory, liquid chlorine can cause chemical burns

• possibilty to form chlorinated hydrocarbons which are carcinogenic /cancer causing (very small risk)

How is bleach made.

Chlorine can be mixed with cold,dilute,aqueous sodium hydroxide to produce sodium hypochlorite. This is a key ingredient in the production of bleach.

revise practicals

OwO i want to die from writing that